216
Surg Neurol 1992 ;38 :216-24
Neurinoma of the Third, Fourth, and Sixth Cranial Nerves : A Survey and Report of a New Fourth Nerve Case Paolo Celli, M .D., Luigi Ferrante, M.D., Michele Acqui, M .D., Luciano Mastronardi, M.D., Aldo Fortuna, M .D., and Lucio Palma, M .D. Department of Neurological Sciences, Division of Neurosurgery, University of Rome La Sapienza, Rome, Italy
Celli P, Ferrante L, Acqui M, Mastronardi L, Fortuna A, Palma L . Neurinoma of the third, fourth, and sixth cranial nerves : a survey and report of a new fourth nerve case . Surg Neurol 1992 ;38:216-24 .
A rare case of trochlear nerve neurinoma is described . Including this case, the number of reported intracranial tumors arising from the sheaths of the third, fourth, and sixth cranial nerves is 38. By site and relationship to the nerve segment, they fall into three groups : cisternal, cisternocavernous, and cavernous . In cisternal tumors of the third and sixth nerves, paresis of the nerve hosting the tumor is the unique nerve deficit ; by contrast, in those of the fourth nerve, paresis of the trochlear nerve can be absent and that of the third nerve present . In the latter tumors, a peculiar ataxic hemiparesis syndrome is produced by midbrain compression . Cisternocavernous neurinomas often cause symptoms of intracranial hypertension, while cavernous neurinomas bring about two clinical features : paresis of one or more nerves of the cavernous sinus and a clinicoradiological orbital apex syndrome . At surgery, generally cisternal neurinomas are totally removed and the nerve source of the tumor identified ; in cisternocavernous and cavernous neurinomas, total removal of tumor and identification of the parent nerve have been reported in only half of the cases . In the majority of parasellar neurinomas, clinical differences can be found between those arising from the nerves governing eye movement and those arising from the gasserian ganglion . KEY WORDS :
Neurinoma ; Schwannoma ; lorracranial tumor ;
Nerve sheath tumor ; Trochlear nerve ; Ataxic hemiparesis
Neurinomas (schwannomas) account for 7%-8% of intracranial tumors [67,71,82] . Most arise from the sensory cranial nerves, chiefly from the vestibular nerve and less commonly from the trigeminal nerve root and gasserian ganglion [2,50,64,67,71,82) . Those arising
Address reprint requests to; Paolo Celli, M .D ., Dipart . Scienze Neurologiche, Div. Neurochirurgia, University di Roma "La Sapienza," Viale dell'Universita 30/A, 1-00185 Roma, Italy . Received July 22, 1991 ; accepted January 16, 1992 .
0 1992 by Elsevier
Science
Publishing Co, Inc.
from the sheaths of the nerves governing eye movements are very uncommon . In 1982, Leunda et al [45) traced only 12 published cases, to which they added four of their own . Other cases have since been reported, and we have been able to find 37 intracranial neurinomas or neurofibromas, definitely or probably originating from the third, fourth, and sixth cranial nerves : 22 from the third [3,8,25,29,31,35,36,38,40,45,47,51,55,60,61,70, 72,73,75,78], 10 from the fourth [7,18,27,39,45,49,68, 76,80), and 5 from the sixth (9,19,21,45,59] (Table 1) . We report the eleventh case of trochlear nerve neurinoma ; this is the second of these tumors-after one of the oculomotor nerve [47]-compared with 13 trigeminal neurinomas observed in our department during the last 50 years . Reviewing the scattered published work on neurinomas of these motor nerves, we attempt to outline the clinical profile and radiological imaging and to analyze the surgical results achieved up to now .
Case Report A 51-year-old man gave a 12-month history of ataxic gait and an 8-month history of a sensation of doughy swelling on the left side of the face and tingling in the left arm . During the 4 months preceding admission, he complained of clumsiness in his left hand and difficulty performing fine movements with it . In the last month diplopia and occasional headache were added. Physical examination on admission yielded no abnormalities, normal blood pressure, and no cutaneous manifestations of von Recklinghausen's disease or evidence of visceral disorders . On neurological examination, the patient was cooperative and well oriented, but his gait was unsteady, broad-based, and swaying, so that he tended to fall to the left . Other findings were : moderate left spastic hemiparesis, more marked in the left lower limb ; left cerebellar dysmetria in the finger-nose test and slowing, incoordination, and awkwardness in the performance of rapid alternating movements of the hand ; and no disorders of sensation, superficial or deep . The poor control of 0090-3019/92 ./55 .00
Surg Neurol
Neurinoma of Cranial Nerves
217
1992 ;38 :216-24
Table 1 . Published Casey of Intracranial Third, Fourth, and Sixth Nerve Neurinomaa
Source (Year) Kovacs [401 (1927) Nagamune et a] [55] (1974) Shuangshori [73] (1975) Kan et al [35) (1976) King [391 (1976) Huber [291 (1978) Case I Case 2 Case 3 Wakabayashi er al [78] (1978) Boggam et al [7) (1979) Schubiger et al [72] (1980) Broggi & Pranzini [8] (1981) Chen [9] (1981) Ho [27] (1981) Samii [68) (1981) ; Samii & Deaf [69] (1989) Hiscott & Simon [25) (1982) Kansu et al [36) (1982) Leunda et at (45) (1982) Case 1 Case 2
Case 3 Case 4 Ishige et al [31) (1985) Nehis et al [59] (1985) Okamoro et al [61] (1985) Satoh et at [70] (1985) Hansman et al [21] (1986) Nogami et a] [60] (1986) Bataille et al [3] (1987) Garen et al [18) (1987) Yamamoto cc al [80] (1987) Ginsberg et at [191 (1988) Tokuriki et al [76] (1988) Maurice-Williams [49] (1989) Katsumata er al [38] (1990) Lunardi et al [47] (1990) Takano et al [75] (1990) Mehta et at [51] (1990) Present report (1992)
Cranial Nerve III III III
Location
IV
Cl CA CI CA CI
III 111 III III IV III III VI IV IV III III
CA CA CI-CA Cl CI CA CI CI CI Cl CI-CA CI
VI 111 IV IV III
CI-CA CI CI CI-CA CA
VI
CI
III III VI III III IV IV VI IV IV III III III III IV
CA CI CA CI CA CI CI CI-CA CI CI CI CI CA Cl-CA CI
IIl
Ahbreviations . CI, cisternal ; CA, cavernous ; Cl-CA, ciuernocavernous .
Figure 1 . (A) Axialand(B)corona/CT scansrhouingaround.hypoderue cystlike lesion at the right sensorial inruura . There is ring enhancement of the lesion after intravenous contrast lnlo .iiou,
movements on the left side was clearly out of proportion to paresis . Ophthalmological examination revealed paralysis of the right trochlear nerve ; the fundi, the visual fields, and visual acuity, were normal . Plain radiographs of the skull showed no abnormalities, but the computed tomographic (CT) scan (Figure 1) imaged a right-sided roundish lesion of cystlike density below the tentorium and connected with it, lying ventrolaterally to the brain stem . Moderate supratentorial hydrocephalus was also present . On intravenous infusion of contrast medium, a ring of increased density appeared around the mass . Vertebral angiography (Figure 2) re-
vealed upward and medial displacement of the right superior cerebellar artery, downward displacement of the anterior inferior cerebellar artery, and slight elevation of the right posterior cerebral artery but no tumor blush . Right temporal craniotomy followed by retraction of the temporal lobe and by transtentorial approach exposed a well-defined, soft, yellowish mass 4 x 3 cm . The tentorium, which adhered to the top of the tumor, was raised . The third nerve and superior cerebellar artery were identified and left intact, but the right trochlear
218
Surg Neurol 1992 ;38: 2 16-24
Celli et al
Figure 2 . (A) Half-axial and (B) lateral preoperative vertebral angiograms show-
ing marked upward and medial displacement of superior cerebellar artery, curved depression of anterior inferior cerebellar artery . and slight elevation of aural and anterior ambient segments of posterior cerebral artery on the right side .
nerve, which was found incorporated in the inferomedial pole of the tumor, could not be spared . The tumor, totally removed, left an impression on the ventrolateral surface of the lower portion of the midbrain and pons . In the first days after the operation, there was transient paralysis of the third nerve on the right side . Later, all the signs and symptoms improved except the paralysis of the superior oblique muscle on the right side . The trochlear nerve paralysis was the only neurological deficit remaining at 5-year follow-up . Histologically, the tumor tissue was made up of compact areas of spindle cells arrayed in bundles, alternating with areas of loosely structured tissue : Antoni type A and type B features . Mitotic activity was absent . The microscopic diagnosis was therefore schwannoma . Discussion With our case, intracranial neurinomas arising from the nerves governing eye movements number 38 : 22 (58%) from the third nerve, 11(29%) from the fourth, and 5 (13%) from the sixth . None of the patients had von Recklinghausen's disease, and none of the tumors presented histological evidence of malignancy . We have not included the case reported by Hasegawa et al [22] of a neurinoma, whose origin from an oculomotor nerve was
uncertain, in a patient with malignant schwannomatosis arising from a spinal neurinoma ; postmortem examination revealed diffuse dissemination of the tumor to the brain, blood vessels, and cranial nerves . Unlike the more frequent vestibular neurinomas [56], those of the third, fourth, and sixth nerves arise as a rule far from the glial-Schwann sheath junction ; this lies less than 4 mm from the neuraxis in the case of the third nerve and not more than 1 mm from the neuraxis in the case of the fourth and sixth nerves [43] . Given the site deduced from the surgical or postmortem report and the radiological findings, we assign these 38 neurinomas to three groups according to the classification proposed by Jefferson [33] for the trigeminal variety : cisternal, that is, confined to the precavernous cisternal segment of the nerve ; cisternocavernous, i .e ., developing in the region of the cavernous sinus and in the retroclival or retropetrosal cisterns ; and cavernous, i .e ., located in the middle cranial fossa on the cavernous or paracavernous segment of the nerve contiguous with or invading the cavernous sinus . This classification seems justified by the uniformity within each group of the clinical and radiological patterns, anatomical relationships, and surgical implications . Of the 38 neurinomas 22 (58%) were classified as cisternal [7-9,18,27,36,38-40,45,47,49,59,60,68,70, 73,76,78,80], 10 (26%) as cavernous [3,21,29,31,35,
Surg Neurol 1992 ;38:2 16-24
Neurinoma of Cranial Nerves
55,61,72,75), and 6 (16%) as cisternocavernous [19,25, 29,45,5 11 (Figure 1) . The third nerve tumors fall equally into cisternal and cavernous ; trochlear nerve neurinomas arise almost exclusively from the cisternal segment of the nerve, while dumbbell tumors in the posterior and middle cranial fossae are relatively more common among abducens neurinomas . Almost all (9 of 10), cavernous neurinomas arise from the third nerve . At surgery, the identification of the nerve from which the tumor arose was possible in all cases of cisternal neurinoma, but only in half (7 of 14) of the cisternocavernous and cavernous neurinomas for which comment on the diagnosis was supplied . In the remainder, one of the nerves subserving eye movement was considered very likely to be the source on the clinical evidence and operative findings, the latter clearly ruling out the ganglion and trigeminal branches as possible sources .
Site and Growth Pattern
Cisternal neurinomas of the oculomotor nerve occupy the interpeduncular cistern and tend to remain medial, as a rule growing upwards into the retroinfundibular and suprasellar spaces, with possible compression of the third ventricle . Almost all neurinomas of the trochlear nerve occupy the cisterna ambiens in the middle incisural space, ventrolaterally to the midbrain and pons below the tentorium ; as they grow, they may extend above the tentorium or medially into the interpeduncular and prepontine cisterns . Only in one case of a small neurinoma found incidentally at necropsy [27] did the tumor lie on the dorsal surface of the midbrain, 1 .5 mm from the point at which the nerve emerged from the brain stem, in the zone of transition between the central and peripheral sheaths of the nerve . Cisternal neurinomas of the abducens nerve occupy the prepontine cistern, between clivus and pons, and tend to push laterally into the upper portion of the cerebellopontine angle . Cisternal neurinomas ranged in size from less than 5 mm to 7 cm . Cavernous neurinomas develop in the parasellar region, compressing or invading the blood vessels and cranial nerves of the cavernous sinus, may grow downward and laterally toward the middle cranial fossa, medially into the sellar cavity and sphenoidal sinus, forward into the orbit through the sphenoidal fissure, or upward into the sylvian sulcus . Cisternocavernous neurinomas extend into the posterior and middle cranial fossae ; those of the third nerve may grow above the sella turcica or into the lateral sulcus, causing compression and displacement of the third ventricle . Four tumors (25,29,45] were almost totally cav-
219
ernous and two retroclival [19,51] . Cisternocavernous and cavernous tumors were generally large . While all cisternal neurinomas are obviously intradural, cisternocavernous and cavernous neurinomas may rarely be extradural after perforating the dura mater of the cavernous sinus or on the floor of the middle cranial fossa 1291 . Clinical Features
The sex ratio of third, fourth, and sixth cranial nerve neurinomas was biased towards females (58% vs . 42%) . The mean age of patients was 43 .8 years, the median age 47 years (minimum 10 years, maximum 70 years) . The peak frequency was in the sixth (30 .5%) and in the fifth (25%) decades of life ; seven patients were under 20 years of age, and none was under 10 years of age . The tumor was found on postmortem examination in two subjects without symptoms with cisternal neurinomas of the third [40] and fourth [27] nerves . In most patients whose clinical history is known, the most frequent first symptom was a deficit of the nerve hosting the tumor : the third in 70% (14/20), the sixth in 60% (3/5), and the fourth in 44% (4/9) . Other initial symptoms were decreased visual acuity or hemiparesis in neurinomas of the third nerve ; ataxia of gait, paresthesias, or hemiparesis in those of the fourth nerve ; and symptoms of intracranial hypertension in those of the sixth nerve . If the decreased visual acuity in cavernous neurinomas is excluded, the nerve bearing the tumor was always the first symptomatic cranial nerve in neurinomas of the third and sixth nerves, while an isolated third nerve deficit is possible in cisternal neurinomas of the trochlear nerve . In cisternal neurinomas, the clinical history was short, under 2 years, in those of the fourth and sixth nerves and very long, 5 years or more, in those of the third . In cisternal neurinomas of the third and sixth nerves, the deficit of the host nerve was an isolated sign or was associated with signs of brain-stem compression, such as Weber syndrome in third nerve tumors, or with symptoms of intracranial hypertension in sixth nerve tumors . Neither trigeminal disturbances nor paresis of other nerves governing eye movements was present in any of the cases . Cisternal neurinoma of the third nerve seems able to cause deficit of the nerve earlier, when it is 5 mm or less in size [36,73] . On the other hand, in less than half of the nine symptomatic cisternal neurinomas of the trochlear nerve was the fourth nerve deficit the presenting symptom or a sign on admission . There were no trigeminal symptoms, but an oculomotor deficit was present in one-third of cases (in one of them, it was the only complaint) [18,45,68], and lastly, on admission one third of patients had no disturbance of eye movement at all [39,49,76] .
2 20
Surg Neurol 1992 ;38 :216-24
Third nerve involvement seems to be related to the medial progression of the tumor into the prepeduncular space or above the posterior clinoid . The absence or late onset of trochlear paralysis, even when the tumor is large, may be due to the length of the cisternal segment of this nerve [431, such that the tumor displaces and twists the nerve fibers instead of destroying them, and the signs of brain-stem compression may appear before or in the absence of paralysis of the nerve . Including our case, six patients with cisternal neurinoma of the trochlear nerve [7,39,49,68,76] presented signs of brain-stem compression, such as gait ataxia, and on the side opposite to the tumor, they had hemiparesis (all six), cerebellar disturbance of the limbs (four cases), and paresthesia with or without deficits of sensation (four cases) . Dysarthria and disturbance of taste were also noticed . Our patient and three others [7,39,49] presented a contralateral combination of hemiparesis and cerebellar limb signs, and three of them had paresthesias, as well . A similar combination of hemiparesis and cerebellar signs, the latter uncommonly contralateral to a nervous system lesion, was first reported by Fisher and Cole [16] in 1965 and named "ataxic hemiparesis" (15) . Since then, this syndrome, broadened to include other accompanying signs such as sensory disorders, gait ataxia, nystagmus, and dysarthria, was described in patients with various intra-axial lesions, principally ischemic and hemorrhagic, more rarely tumors [62], at the site where the pyramidal fibers run close to those of cerebrocerebellocerebral loop . The cerebellar symptoms are attributed to contralateral damage to the temporoparietopontine fibers in the posterior limb of the internal capsule, to the thalamic nuclei, to the thalamocortical projections [28,30,34,53,65], to the pontine nuclei, or to the pontocerebellar fibers [15] and, in the few reported cases of "midbrain ataxic hemiparesis" [4,23,241, as well as in Claude's mesencephalic syndrome [17], to impairment of crossed ascending dentatorubrothalamic fibers by an intra-axial lesion in the rostral midbrain . On the other hand, in cases of cisternal neurinoma of the fourth nerve, the ataxic hemiparesis syndrome is likely caused by extra-axial compression of the caudal midbrain . In fact, the radiological images and operative records show the tumor to be wholly or almost wholly below the tentorium, connected to the midbrain and pons . The compressive force of the mass thus seems to be exerted on the anterior lateral surface of the basis pedunculi (the middle segment of which houses the pyramidal tract and the lateral segment, the temporoparietooccipitopontine fibers [ 11,48]) and of the midbrain tegumentum (along which run the spinothalamic tract, the ascending tract of the trigeminus, and the medial lemniscus with its gustatory component [11]) .
Celli et al
The slow extrinsic compression exerted by the mass accounts for the long tract signs, for their mildness, and for their rapid regression after removal of the neurinoma ; furthermore, it accords with the absence of disturbances of conjugated gaze and of the oculomotor nerve . The homolateral combination of hemiparesis, cerebellar ataxia, and sensory disturbances in the presence of an extra-axial tumor at the tentorial notch is more strongly suggestive of a trochlear neurinoma than the actual nerve deficit, which in any case is missing in half of the patients with these signs . Further, these are the only cases traced in the literature of ataxic hemiparesis syndrome produced by a benign extra-axial infratentorial tumor . Of the six cisternocavernous neurinomas only one arising from the fourth nerve [451 presented a deficit of the nerve that gave rise to the tumor as the sole symptom . In almost all others, there was clinical or radiological evidence of intracranial hypertension, sometimes associated with contralateral hemiparesis, with disorders of other nerves of the cavernous sinus, or because of extension of the tumor into the suprasellar area and sylvian cistern, with aphasia and hemianopia . The 10 cavernous neurinomas, nine arising from the third nerve and one from the sixth, supplied two clinical patterns . One group of five patients [21,31,55,72,751, in whom the tumor was confined to the parasellar area, reached diagnosis with the deficit of the nerve hosting the tumor as an isolated sign, or sometimes with involvement of another of the nerves governing eye movement or of the ophthalmic nerve . Another group of five patients [3,29,35,61], with third nerve neurinoma and frequently with extension of the tumor into the posterior portion of the orbit, on admission presented exophthalmos and oculomotor nerve deficit, combined with more or less complete involvement of the other nerves of the superior orbital fissure and of the optic nerve (orbital apex syndrome) . In three of these patients, the first symptom was the oculomotor nerve deficit, and in the other two it was a decrease in visual acuity . The preoperative history was long, from 18 months to 20 years, and the radiographic findings were often striking, with widening of the superior orbital fissure or erosion of the floor of the middle cranial fossa. The difference in clinical pattern and in length of history points to early diagnosis in the first group and to an advanced stage of the disease and late diagnosis in the second .
Radiological Findings In cisternal neurinomas, the roentgenograms of the skull were generally negative . Cerebral angiography [7, 8,18,36,38,39,47,59,60,70,73,76,78,80] in large tumors revealed marked displacements of the superior cerebellar artery ; shifts of the posterior cerebral artery,
Neurinoma of Cranial Nerves
anterior inferior cerebellar artery, or basilar trunk were mild and less frequent . A tumor blush was seen in only one of the 15 cases studied . The skull radiography or CT scan of cisternocavernous and cavernous neurinomas showed circumscribed lesions of the sellar bones, clinoids, or tip of the petrous bone in half of the first group [29,45,51] and more conspicuous bone changes, such as widening of the superior orbital fissure and sometimes erosion of the floor of the middle cranial fossa, in some of the second group [3,29,35,61] . Shubiger et al [72] observed that erosion of the temporal fossa or the presence of a large tumor attachment to the floor of the middle cranial fossa rules out a neurinoma of the third, fourth, and sixth cranial nerves and clinches the diagnosis of trigeminal neurinoma ; this may well hold good for small neurinomas confined to the parasellar area but does not for larger tumors . Cisternocavernous [25,29] and cavernous 13,29 55,61,72,751 neurinomas studied by angiography commonly produced stretching and displacement downward and forward, and as a rule medially, of the intracavernous carotid artery, associated with upward and forward displacement of the supraclinoid carotid . In half of these neurinomas, the middle cerebral artery was stretched or elevated in the M1 segment . Pathological vessels were present in about half (4 of 10) patients . CT scan studies [3,7,8,18,19,21,25,29,31,38,45,47, 49,51,59-61,68,70,72,75,76,80] without contrast medium presented the variable pattern of neurinomas : low density, normal brain density, mixed normal and low density, or even high density . After contrast infusion, in all but one there was an increase in density, either uniform, patchy, or peripheral, very marked in some parasellar neurinomas . CT scan did not visualize a very small (3 X 4 mm) neurinoma causing third nerve palsy [36] . This possibility that neurinoma of the third nerve can become symptomatic when so small [36,73] that it could be undetected initially strongly indicates repeated neuroimaging studies in patients with acquired cryptogenetic oculomotor nerve deficit [1] . Almost never did clinical information and diagnostic imaging suggest a third, fourth, or sixth nerve tumor . In addition, in some cisternal neurinomas of the third and fourth nerves, CT scanning and angiography failed to dispel the doubt that the tumor might be intrinsic to the brain stem [8, 18, 47], something that magnetic resonance imaging (MRI) may do . In four patients [18,19,38,76], MRI depicted the lesion, which was extra-axial in all, as hyperintense on the T2-weighted image but isointense, hypointense, or hyperintense on the TI-weighted image . In several cisternocavernous and cavernous neurinomas, the preoperative diagnosis was meningioma (para-
Surg Neurol 1992 ;38 :216-24
221
sellar, of the lesser sphenoid wing, or of the cavernous sinus), because of the pathologial circulations imaged by angiography or the hyperdensity of the tumor on the CT scan before or after contrast infusion, Surgery In cisternal neurinomas of the third and fourth nerves, the surgical approach was subtemporal, transtentorial, frontotemporal, and rarely . suboccipital ; in two of the sixth nerve tumors, subtemporal and suboccipital approaches were used . Tumor removal was nearly always total ; in a few cases, fragments of pathological tissue adhering to blood vessels or to the brain stem were left behind . In cisternocavernous and cavernous neurinomas, the approach was subtemporal or frontotemporal in the former and frontotemporal in the latter . Only in about 50% of these was total removal reported, because the tumor tissue invaded the cavernous sinus or was firmly adherent to the carotid or middle cerebral artery . There was only one operative death, but almost all patients were left with deficit of the nerve from which the tumor arose . As a rule, the nerve was disrupted or sacrificed, its continuity being conserved in only two cases, cisternal neurinomas of the fourth [69] and sixth [9] nerves . In the case reported by Samii and by Samii and Draf [68,69], it was possible to dissect the tumor from the trochlear nerve and spare the uninvolved fascicles . The 50% chance of complete removal of parasellar neurinomas of the third, fourth, and sixth cranial nerves is similar to that reported for parasellar neurinomas of the fifth nerve in a recent review of the literature [74] . However it is possible that today's surgical techniques will make possible both total excision and anatomical preservation of the cranial nerves in the majority of paracavernous tumors . When disruption of one of the nerves subserving eye movement occurs during removal of a neurinoma, microsuture of the nerve should be attempted, because good functional results have been reported [13,20,32] ; in the case of the fourth and sixth nerves, the chances of functional recovery should be greater, since these nerves are purely motor, supply a single muscle, and are composed, in the majority of cases, of a single fascicle [57,58] . There was only one recurrence [77], 13 years after apparently total removal of a cisternal neurinoma of the third nerve [45], but there is no long-term follow-up information on the cases of incomplete tumor removal. Clinical Differences and Similarities Between Parasellar Neurinomas of the Third, Fourth, and Sixth Nerves and Those of the Fifth Nerve Boggam et al [7] suggested that intracranial neurinomas of the nerves governing eye movement were rare he-
222
Surg Neurol
Celli et al
1992 ;38 :216-24
cause they were probably mistaken for the more com-
regress after the removal of trigeminal neurinomas
mon trigeminal neurinomas . In fact, about one third of
[14,37,74,81] than after the removal of oculomotor,
patients with cisternocavernous and cavernous neurino-
trochlear, or abducens neurinomas.
mas present with paresthesias, pain, or more rarely, trigeminal hypesthesia, while some 50% of patients with neurinoma of the gasserian ganglion present a deficit of one or more of the nerves governing eye movement
References
[5,42,44,50,64,71,74] . However, in parasellar neurinomas of the third, fourth, and sixth nerves, the deficit of
1 . Abdul-Rahim AS, Savino PJ, Zimmerman RA, Sergort RC, Bosley TM . Cryptogenic oculomotor nerve palsy . The need for repeated neuroimaging studies . Arch Ophthalmol 1989 ;107 :387-90 .
the nerve that give rise to the tumor is always present
2 . Arseni C, Dumirrescu L, Costantinescu A . Neurinomas of the rrigeminal nerve . Surg Neurol 1975 ;4 :497-503 . 3 . Bataille B, Muckensturm B, Roualdes G, Maissin F, Deglaire B, Desbordes JM . Neurinome du nerf oculomoteur . A propos d'un cas . Neurochirurgie 1987 ;33 :405-7 .
on examination, and this nerve is always the first symptomatic cranial nerve, if the visual deficit in cavernous neurinomas is excluded . The trigeminal symptom, when observed, is confined to the first division, is never the first symptom, is never isolated, and is hardly ever a deficit . In neurinomas of the gasserian ganglion, by contrast, a third or fourth nerve deficit never seems to have been reported as an isolated symptom and is very rarely (3%) reported as the first symptom of the disease [741, Paresis
of the abducens nerve, although a common symptom, being the first symptom in one fifth of cases and the second most frequent on admission [741, is rarely an isolated sign or symptom of onset, followed by a trigeminal disturbance confined to the first division [14,26,37,
50,54,64,81] . Among middle fossa neurinomas that produce exophthalmos (rarer now because of early diagnosis), there are no clinical differences between those arising from the third nerve and those arising, with an incidence of
11%-17% [12,50,74], from the gasserian ganglion [2,5,6,10,41,46,52,7 11 and more rarely from the intracranial ophthalmic division [44,641 . They usually have the following points in common : a long preoperative history, a possible third nerve deficit or reduction of visual acuity at onset, trigeminal disorders often absent or limited to the first branch, and on admission a more or less complete clinical-radiological pattern of orbital apex syndrome . At an advanced stage of the disease, the angiographic changes in the parasellar carotid artery do not differ between neurinomas of the third nerve and those of the gasserian ganglion . In small tumors, however, distinctive points to look for are elevation of the supraclinoid intradural carotid artery, with enlargement of the upper curve of the carotid siphon, for the third nerve neurinoma and displacement and stretching of the extradural ganglionic carotid artery for neurinoma of the gasserian ganglion
[63,66,791 . At operation, parasellar neurinomas of the third, fourth, and sixth nerves usually appear to be intradural, while those of the gasserian ganglion are extradural . Lastly, the preoperation deficit of eye movement, especially in the case of the sixth nerve, is more likely to
4 . Bendheim PE, Berg BO . Ataxic hemiparesis from a midbrain mass . Ann Neurol 1981 ;9 :405-6 . 5 . De Benedettis G, Bernasconi V, Ettorre G . Turnouts of the fifth cranial nerve . Area Neurochir (Wien) 1977 ;38 :37-64 . 6 . Bernasconi V, Papo 1, Beduschi A, D'Andrea F . I neurinomi del trigemino. Chirurgia 1957 ;12 :405-26 . 7 . Boggam JE, Rosenblum ML, Wilson CB . Neurilemmoma of the fourth cranial nerve . Case report . J . Neurosurg 1979;50 :519-21 . 8 . Broggi G, Franzini A . Value of serial stereotactic biopsies and impedance monitoring in the treatment of deep brain tumours . J Neurol Neurosurg Psychiatry . 1981 ;44 :397-401 . 9 . Chen BH . Neurinoma of the abducens nerve . Neurosurgery 198 1 ;9 :64-6 . 10 . Cohen I . Tumours involving the Gasserian ganglion . J Nerv Menr Dis 1933 ;78 :492-9 . 11 . Crosby EC, Humphrey T, Laner EW . Correlative anatomy of the nervous system . New York : Macmillan, 1962 :731 . 12 . Dany A, Pefferkorn JP, Vallat JN, Loubet R, Maudoux M . Ncurinome du ganglion de Gasser a developpement temporal . Neurochirurgie 1970 ;4 :349-56. 13 . Deruty R, Guyotat J, Mottolose C, Bady B, Girard Madoux M, Vigherto A, Vila A . Recuperation partielle du nerf moteur oculaire common apres section puis reparation au tours de Fexerese dune tumeur. Neurochirurgie 1988 ;34 :287-92 . 14. Findler G, Feinsod M, Sahar A . Trigeminal neurinoma with unusual presentation . Report of a case with trigeminal somatosensory-evoked response. Surg Neurol 1983 ;19 :351-3 . 15 . Fisher CM . Ataxic hemiparesis . A pathologic study . Arch Neural 1978 ;35 :126-8 . 16. Fisher CM, Cole M . Homolateral ataxia and crural paresis : a vascular syndrome . J Neurol Neurosurg Psychiatry 1965 ; 28 :48-55 . 17 . Fog M, Hein-Sorensen 0 . Mesencephalic syndromes . In : Vinken PJ, Bruyn GW, eds : Handbook of clinical neurology-localization in clinical neurology, vol 2 . Amsterdam : North-Holland, 1969 :272-85 . 18. Garen PD, Harper CG, Teo C, Johnston IH . Cystic schwannoma of the trochlear nerve mimicking a brain-stem tumor . Case report. J Neurosurg 1987 ;67 :928-30 . 19. Ginsberg F, Peysrer RG, Rose WS, Drapkin AJ . Sixth nerve schwannoma: MR and CT demonstration . J Comput Assist Tomogr 1988 ;12 :482-4 . 20. Grimson BS, Ross MJ, Tyson G . Return of function after intracranial suture of the rrochlcar nerve . Case report . J Neurosurg 19K61 191-2 . 21 . Hausman ML, Hoover ED, Peysrer RG . Sixth nerve neuroma in the cavernous sinus : CT features . Case report. J Comput Assist Tomogr 1986 ;10x030-2 .
Neurinoma
of Cranial
Nerves
22 . Hasegawa H, Bitch S, Otsuki H, Fujiwara M, Yamamoto T, Kobayashi Y . Catecholamine-secreting malignant schwannoma in a patient with multiple intracranial aneurysms . Case report . J Neurosurg [984 ;60 :1089-94 . 23 . Helweg-Larsen S, Larsson H, Henriksen 0, Sorensen PS . Ataxic hemiparesis : three different locations of lesions studied by MRI . Neurology 1988 ;38 :1322-4 .
Surg Neurol 1992 ;38 :216-24
2 23
45 . Leunda G, Vaquero J, Cabezudo J, Garcia-Uria J, Bravo G . Schwannoma of the oculomotor nerve . Report of four cases . J Neurosurg 1982 ;57 :563-5 . 46 . Loew F, Tennis W . Klinik and Behandlung der Neurinome des Nervus trigeminus . Zentralbl Neurochir 1954 ;14 :32-41 . 47 . Lunardi P, Rocchi G, Rizzo A, Missori P . Neurinoma of the oculomotor nerve. Clin Neurol Neurosurg 1990 ;92-4 :333-5 .
24 . Hershkowitz N, Bergey GK, Josyln J, Evans D . Isolated midbrain lesion resulting from closed head injury : a unique presentation of ataxic hemiparesis . Neurology 1989 ;39 :452-3 .
48 . Maria OS, Angevine JB, Locke S . Topographical organization of the lateral segment of the basis pedunculi in man . J Comp Neurol 1962 ;118 :165-83 .
25 . Hiscott P, Simon L: An unusual presentation of neurofibroma of the oculomotor nerve . J Neurosurg 1982 ;56:854-6 .
49 . Maurice-Williams RS . Isolated schwannoma of the fourth cranial nerve : case report. J Neurol Neurosurg Psychiatry 1989 ; 52 :1442-3 .
26 . Hitchon PW, Graf CJ, McCabe BE, Namba K . Trigeminal neurilemmoma presenting as a sphenoid sinus mass . Surg Neurol 1979 ;11 :305-7 . 27 . Ho KL . Schwannnmaof the trochlear nerve . Case report j Neurosurg [981 ;55 ;132-5 . 28 . Hommel M, Gaio JM, Pollak P, Borgel F, Perret J : H€mipar€sie ataxique par lacune rhalamique . Rev Neurol (Paris) 1987 ;143 : 602-4 . 29 . Huber A . Das Okulomotoriusneurinom . Min Monatsbl Augenheilkd 1978 ;172 :627-35 . 30 . Iragui VJ, McCurchen CB . Capsular ataxic hemiparesis . Arch Neurol 1982 ;39 :528-9 . 31 . Ishige N, Ito L, Saeki N, Oka N . Neurinoma Nith intrasellar extension : a case report . No Shinkei Geka 1985 ;13 :79-84 (in Japanese). 32 . Iwabuchi T, Suzuki M, Nakaoka T, Suzuki S . Oculomotor nerve anastomosis . Neurosurgery 1982 ;10 :490-1 . 33 . Jefferson G . Trigeminal neurinomas with some remarks on malignant invasion of the Gasserian ganglion . Proc Congr Neurol Surg 1955 ;1 :11-54 . 34 . Jokelainen M, Pilke A . Ataxic hemiparesis . Arch Neurol [983 ;40 :326 (letter) . 35 . Kan T, Kouki T, Yamada H, Hirakawa K . Neurinoma of the oculomotor nerve . Case report . Rinsho Shinkeigaku 1976 ;16:540 (in Japanese) . Cited in : Katsumata Y, Maehara T, Noda M, Shirouzu 1 . N eurinoma of the oculomotor nerve : CT and MR features . Case report. J Comput Assist Tomogr 1990 ;14 :658-61 . 36 . Kansu T, Ozcan OE, Ozdirim E, Cool B, Gurcay O . Neurinoma of the oculomotor nerve . Case report . J Clin Neuro Ophthalmol 1982 ;2 :271-2 . 37 . Katoh M, Kadoya S, Emori T, Kwak R . Trigeminal neurinoma presenting abducens nerve palsy as initial symptom : a report of two cases . No Shinkei Geka 1985 ;13 :555-60 (in Japanese). 38 . Katsumata Y, Maehara T, Noda M, Shirouzu L Neurinoma of the oculomotor nerve : CT and MR features . Case report. J Compur Assist Tomogr 1990 ;14 :658-61 . 39 . King JS . Trochlear nerve sheath tumor . Case report. J Neurosurg 1976 ;44 :245-7 . 40 . Kovacs W . Ueber ein solirares Neurinom des Nervus oculomotorius . Zentralbl AlIg Pathol 1927 ;40 :518-22 . 41 . Kraft H. Bench uber einen Fall von Neurofibromatose mit orbitookularen Symptomen and sekundaren Sellaveranderungen . Klin Monatsbl Augenheilkd 1970 ;156 :112-8. 42 . Krayenbuhl H . Primary tumors of the root of the fifth cranial nerve : their distinction from tumors of the gasserian ganglion . Brain 1936 ;59 :337-52 . Lang J . Uber Ban, Lange and Gefassbeziehungen der "zentralen" and "peripheren" Strecken der intrazisternalen Hirnnerven . Zentralbl Neurochir [982 ;43 :217-55 . 44 . Lesoin F, Rousseaux M, Villetre L, Aurricque A, Dhellemmes P . Pellerin P, Vaneecloo JM, Leys D, Jomin M . Neurinomas of the trigeminal nerve . Acts, Neurochir (Wien) 1986 ;82 :118-22 .
50 . McCormick PC, Bello JA, Post KD . Trigeminal schwannoma . Surgical series of 14 cases with review of the literature . J Neurosurg 1988;69 :850-60 . 51 . Mehta VS, Singh RVP, Misra NK, Choudhary C . Schwannnmaof the oculomotor nerve . Br J Neurosurg 1990 ;4 :69-72 . 52 . Mello LR, Tanze A . : Some aspects of trigeminal neurinomas . Neuroradiology 1972 :4 :215-21 . 53 .
Man
E, Yamadori A, Kudo Y, Tabuchi M . Ataxic hemiparesis from small capsular hemorrhage. Computed tomography and somatosensory evoked potentials . Arch Neurol 1984 :41 :1050-3 .
54 . Morniroli G . Das Trigeminusneurinom . Schweiz Arch Neurol Neurochir Psychiatr 1970 ;107 :17-86 . 55 . Nagamune A, Kuwana N, Kuwahara R. Neurinoma of the oculomotor nerve . Case report. Rinsho Shinkegaku 1974 ;11 :195 (in Japanese) . Cited in : Nogami K, Nishijima M . Endo 5, Takaku A . Neurinoma of the oculomotor nerve . Case report . No Shinkei Geka 1986 ;14 :1237-41 (in Japanese) . 56. Nager GT . Acoustic neurinomas . Pathology and differential diagnosis . Arch Otolaryngol 1969 ;89:252= 9 . 57 . Nathan H, Goldhammer Y . The rootlets of the rrochlear nerve ; anatomical observations in human brains_ Acra Anar 1973 ;84 : 590-6 . 58 . Nathan H, Ouaknine G, Kosary JZ . The abducens nerve : anatomical variations in its course . J Neurosurg 1974 ;41 :561-6 . 59 . Nehls DG, Sonntag VKH, Murphy AR, Johnson PC, Waggener JD . Fibroblastic tumor of the abducens nerve . Case report . J Neurosurg 1985 ;62 :296-99 . 60 . Nogami K, Nishijima M, Endo S, Takaku A . Neurinoma of the oculomotor nerve . Case report . No Shinkei Geka 198G14 : 1237-41 (in Japanese) . 61 . Okamoto S, Handa H, Yamashira J . Neurinoma of the oculomotor nerve . Surg Neurol 1985 :24 :275-8 . 62 . Orgogozo JM, Bogousslavsky J . Lacunar syndromes. In : Vinken P3, Bruyn GW, Klawans HL, eds : Handbook of clinical neurology-vascular diseases, part IT, vol 54 . Amsterdam : Elsevier, 1989 :235-69 . 63 . Palacios E, MacGee EE . The radiographic diagnosis of trigeminal neurinomas . J Neurosurg 1972 :36:153-6. 64 . Pollack F . Sekhar LN, Jannerta P3 . Janecka IP . Neurilemomas of the trigeminal nerve . J Neurosurg 1989 ;70 :737 -45 . 65 . De Renzi E, Nichelli P, Crisi G . Hemiataxia and crural hemiparesis following capsular infarct J Neurol Neurosurg Psychiatry 1983 ;46 :561-3 . 66 . Ruherti R, Galligiont F, Carreri A . Considerations radiologiques clans les neurinomes du ganglion de Gasser . Acres Radiol Diagn 1966 ;5 :465-9 . 67 . Russel DS, Rubinstein I .J . Pathology of tumors of the nervous system, 4th ed . Edinburgh : Edward Arnold, 1977 :44868 . Samii M . Intracranial compression of the third, fourth and sixth cranial nerves by tumors . In : Samii M . Jannetta PJ, eds : Cranial
224
Surg Neurol 1992 ;38 :216-24
nerves: anatomy, pathology, pathophysiology, diagnosis, treatment. Berlin : Springer-Verlag, 1981 :241-8 . 69. Samii M, Draf W. Surgery of the skull base . Berlin : SpringerVerlag, 1989 :335-7 . 70 . Satoh K, Saitoh S, Satoh K, Yamada K, Nakai A. Neurinoma of the oculomotor nerve causing ophthalmoplegic migraine . Med Consult New Remed (Tokyo) 1985 ;22 :1062-6 (in Japanese) . 71 . Schisano G, Olivecrona H . Neurinomas of the gasserian ganglion and trigeminal root. J Neurosurg 1960 ;17 :306-22 . 72 . Schubiger 0, Valavanis A, Hayek J, Dabir K. Neuroma of the cavernous sinus . Surg Neurol 1980 ;13 :313-6. 73 . Shuangshoti S, Neurilemmoma of the oculomoror nerve . Br J Ophthalmol 1975 ;59 :64-6. 74 . Sindou M, Pelissou 1 . Trigeminal neurinomas . A special type of cavernous sinus tumors . In : Dolenc VV, ed : The cavernous sinus . Vienna: Springer-Verlag, 1987 :355-76 . 75 . Takano S, Endo M, Miyasaka Y, Yada K, Ohwada T, Takagi H . Neurinoma of the oculomotor nerve . Case report. Neurol Med Chir (Tokyo) 1990 ;30 :132-6 .
Celli et al
76. Tokuriki Y, Yamashita J, Kikuchi H, Asaro R, Handa H . Trochlear nerve neurinoma. Case report . Neurol Med Chir (Tokyo) 1988 ;28 :70-3 . 77 . Vaquero J, Martinez R, Salazar J . Suprasellar recurrence of third nerve neurinoma. J Neurosurg 1985 ;62 :317 (letter). 78. Wakabayashi S, Misawa I, Uno A, Hananouchi M . Schwannoma of the oculomotor nerve with a cerebral aneurysm . Case report. Rinsho Shinkeigaku 1978 ;18 :433 (in Japanese). Cited in : Katsumata Y, Maehara T, Noda M, Shirouzu 1 . Neurinoma of the oculomotor nerve : CT and MR features . Case report. J Comput Assist Tomogr 1990 ;14 .658-61 . 79. WestbergG .Angiographicchanges inneurinomaofthetrigeminal nerve . Acta Radial Diagn 1963 ;1 :513-20. 80. Yamamoto M, Jimbo M, Ide M, Kubo O . Trochlear neurinoma. Surg Neurol 1987 ;28 :287-90 . 81 . Yamashita J, Asato R, Handa H, Nakao S, Ogata M . Abducens nerve palsy as initial symptom of trigeminal schwannoma . J Neurol Neurosurg Psychiatry 1977 40 :1190-7 . 82 . Zulch KJ . Brain tumors : their biology and pathology, 3rd ed . Berlin : Springer-Verlag, 1986 :704 .
Surg Neurol 1992 ;38 :216-24
Neurinoma of the Third, Fourth, and Sixth Cranial Nerves : A Survey and Report of a New Fourth Nerve Case Paolo Celli, M .D., Luigi Ferrante, M.D., Michele Acqui, M .D., Luciano Mastronardi, M.D., Aldo Fortuna, M .D., and Lucio Palma, M .D. Department of Neurological Sciences, Division of Neurosurgery, University of Rome La Sapienza, Rome, Italy
Celli P, Ferrante L, Acqui M, Mastronardi L, Fortuna A, Palma L . Neurinoma of the third, fourth, and sixth cranial nerves : a survey and report of a new fourth nerve case . Surg Neurol 1992 ;38:216-24 .
A rare case of trochlear nerve neurinoma is described . Including this case, the number of reported intracranial tumors arising from the sheaths of the third, fourth, and sixth cranial nerves is 38. By site and relationship to the nerve segment, they fall into three groups : cisternal, cisternocavernous, and cavernous . In cisternal tumors of the third and sixth nerves, paresis of the nerve hosting the tumor is the unique nerve deficit ; by contrast, in those of the fourth nerve, paresis of the trochlear nerve can be absent and that of the third nerve present . In the latter tumors, a peculiar ataxic hemiparesis syndrome is produced by midbrain compression . Cisternocavernous neurinomas often cause symptoms of intracranial hypertension, while cavernous neurinomas bring about two clinical features : paresis of one or more nerves of the cavernous sinus and a clinicoradiological orbital apex syndrome . At surgery, generally cisternal neurinomas are totally removed and the nerve source of the tumor identified ; in cisternocavernous and cavernous neurinomas, total removal of tumor and identification of the parent nerve have been reported in only half of the cases . In the majority of parasellar neurinomas, clinical differences can be found between those arising from the nerves governing eye movement and those arising from the gasserian ganglion . KEY WORDS :
Neurinoma ; Schwannoma ; lorracranial tumor ;
Nerve sheath tumor ; Trochlear nerve ; Ataxic hemiparesis
Neurinomas (schwannomas) account for 7%-8% of intracranial tumors [67,71,82] . Most arise from the sensory cranial nerves, chiefly from the vestibular nerve and less commonly from the trigeminal nerve root and gasserian ganglion [2,50,64,67,71,82) . Those arising
Address reprint requests to; Paolo Celli, M .D ., Dipart . Scienze Neurologiche, Div. Neurochirurgia, University di Roma "La Sapienza," Viale dell'Universita 30/A, 1-00185 Roma, Italy . Received July 22, 1991 ; accepted January 16, 1992 .
0 1992 by Elsevier
Science
Publishing Co, Inc.
from the sheaths of the nerves governing eye movements are very uncommon . In 1982, Leunda et al [45) traced only 12 published cases, to which they added four of their own . Other cases have since been reported, and we have been able to find 37 intracranial neurinomas or neurofibromas, definitely or probably originating from the third, fourth, and sixth cranial nerves : 22 from the third [3,8,25,29,31,35,36,38,40,45,47,51,55,60,61,70, 72,73,75,78], 10 from the fourth [7,18,27,39,45,49,68, 76,80), and 5 from the sixth (9,19,21,45,59] (Table 1) . We report the eleventh case of trochlear nerve neurinoma ; this is the second of these tumors-after one of the oculomotor nerve [47]-compared with 13 trigeminal neurinomas observed in our department during the last 50 years . Reviewing the scattered published work on neurinomas of these motor nerves, we attempt to outline the clinical profile and radiological imaging and to analyze the surgical results achieved up to now .
Case Report A 51-year-old man gave a 12-month history of ataxic gait and an 8-month history of a sensation of doughy swelling on the left side of the face and tingling in the left arm . During the 4 months preceding admission, he complained of clumsiness in his left hand and difficulty performing fine movements with it . In the last month diplopia and occasional headache were added. Physical examination on admission yielded no abnormalities, normal blood pressure, and no cutaneous manifestations of von Recklinghausen's disease or evidence of visceral disorders . On neurological examination, the patient was cooperative and well oriented, but his gait was unsteady, broad-based, and swaying, so that he tended to fall to the left . Other findings were : moderate left spastic hemiparesis, more marked in the left lower limb ; left cerebellar dysmetria in the finger-nose test and slowing, incoordination, and awkwardness in the performance of rapid alternating movements of the hand ; and no disorders of sensation, superficial or deep . The poor control of 0090-3019/92 ./55 .00
Surg Neurol
Neurinoma of Cranial Nerves
217
1992 ;38 :216-24
Table 1 . Published Casey of Intracranial Third, Fourth, and Sixth Nerve Neurinomaa
Source (Year) Kovacs [401 (1927) Nagamune et a] [55] (1974) Shuangshori [73] (1975) Kan et al [35) (1976) King [391 (1976) Huber [291 (1978) Case I Case 2 Case 3 Wakabayashi er al [78] (1978) Boggam et al [7) (1979) Schubiger et al [72] (1980) Broggi & Pranzini [8] (1981) Chen [9] (1981) Ho [27] (1981) Samii [68) (1981) ; Samii & Deaf [69] (1989) Hiscott & Simon [25) (1982) Kansu et al [36) (1982) Leunda et at (45) (1982) Case 1 Case 2
Case 3 Case 4 Ishige et al [31) (1985) Nehis et al [59] (1985) Okamoro et al [61] (1985) Satoh et at [70] (1985) Hansman et al [21] (1986) Nogami et a] [60] (1986) Bataille et al [3] (1987) Garen et al [18) (1987) Yamamoto cc al [80] (1987) Ginsberg et at [191 (1988) Tokuriki et al [76] (1988) Maurice-Williams [49] (1989) Katsumata er al [38] (1990) Lunardi et al [47] (1990) Takano et al [75] (1990) Mehta et at [51] (1990) Present report (1992)
Cranial Nerve III III III
Location
IV
Cl CA CI CA CI
III 111 III III IV III III VI IV IV III III
CA CA CI-CA Cl CI CA CI CI CI Cl CI-CA CI
VI 111 IV IV III
CI-CA CI CI CI-CA CA
VI
CI
III III VI III III IV IV VI IV IV III III III III IV
CA CI CA CI CA CI CI CI-CA CI CI CI CI CA Cl-CA CI
IIl
Ahbreviations . CI, cisternal ; CA, cavernous ; Cl-CA, ciuernocavernous .
Figure 1 . (A) Axialand(B)corona/CT scansrhouingaround.hypoderue cystlike lesion at the right sensorial inruura . There is ring enhancement of the lesion after intravenous contrast lnlo .iiou,
movements on the left side was clearly out of proportion to paresis . Ophthalmological examination revealed paralysis of the right trochlear nerve ; the fundi, the visual fields, and visual acuity, were normal . Plain radiographs of the skull showed no abnormalities, but the computed tomographic (CT) scan (Figure 1) imaged a right-sided roundish lesion of cystlike density below the tentorium and connected with it, lying ventrolaterally to the brain stem . Moderate supratentorial hydrocephalus was also present . On intravenous infusion of contrast medium, a ring of increased density appeared around the mass . Vertebral angiography (Figure 2) re-
vealed upward and medial displacement of the right superior cerebellar artery, downward displacement of the anterior inferior cerebellar artery, and slight elevation of the right posterior cerebral artery but no tumor blush . Right temporal craniotomy followed by retraction of the temporal lobe and by transtentorial approach exposed a well-defined, soft, yellowish mass 4 x 3 cm . The tentorium, which adhered to the top of the tumor, was raised . The third nerve and superior cerebellar artery were identified and left intact, but the right trochlear
218
Surg Neurol 1992 ;38: 2 16-24
Celli et al
Figure 2 . (A) Half-axial and (B) lateral preoperative vertebral angiograms show-
ing marked upward and medial displacement of superior cerebellar artery, curved depression of anterior inferior cerebellar artery . and slight elevation of aural and anterior ambient segments of posterior cerebral artery on the right side .
nerve, which was found incorporated in the inferomedial pole of the tumor, could not be spared . The tumor, totally removed, left an impression on the ventrolateral surface of the lower portion of the midbrain and pons . In the first days after the operation, there was transient paralysis of the third nerve on the right side . Later, all the signs and symptoms improved except the paralysis of the superior oblique muscle on the right side . The trochlear nerve paralysis was the only neurological deficit remaining at 5-year follow-up . Histologically, the tumor tissue was made up of compact areas of spindle cells arrayed in bundles, alternating with areas of loosely structured tissue : Antoni type A and type B features . Mitotic activity was absent . The microscopic diagnosis was therefore schwannoma . Discussion With our case, intracranial neurinomas arising from the nerves governing eye movements number 38 : 22 (58%) from the third nerve, 11(29%) from the fourth, and 5 (13%) from the sixth . None of the patients had von Recklinghausen's disease, and none of the tumors presented histological evidence of malignancy . We have not included the case reported by Hasegawa et al [22] of a neurinoma, whose origin from an oculomotor nerve was
uncertain, in a patient with malignant schwannomatosis arising from a spinal neurinoma ; postmortem examination revealed diffuse dissemination of the tumor to the brain, blood vessels, and cranial nerves . Unlike the more frequent vestibular neurinomas [56], those of the third, fourth, and sixth nerves arise as a rule far from the glial-Schwann sheath junction ; this lies less than 4 mm from the neuraxis in the case of the third nerve and not more than 1 mm from the neuraxis in the case of the fourth and sixth nerves [43] . Given the site deduced from the surgical or postmortem report and the radiological findings, we assign these 38 neurinomas to three groups according to the classification proposed by Jefferson [33] for the trigeminal variety : cisternal, that is, confined to the precavernous cisternal segment of the nerve ; cisternocavernous, i .e ., developing in the region of the cavernous sinus and in the retroclival or retropetrosal cisterns ; and cavernous, i .e ., located in the middle cranial fossa on the cavernous or paracavernous segment of the nerve contiguous with or invading the cavernous sinus . This classification seems justified by the uniformity within each group of the clinical and radiological patterns, anatomical relationships, and surgical implications . Of the 38 neurinomas 22 (58%) were classified as cisternal [7-9,18,27,36,38-40,45,47,49,59,60,68,70, 73,76,78,80], 10 (26%) as cavernous [3,21,29,31,35,
Surg Neurol 1992 ;38:2 16-24
Neurinoma of Cranial Nerves
55,61,72,75), and 6 (16%) as cisternocavernous [19,25, 29,45,5 11 (Figure 1) . The third nerve tumors fall equally into cisternal and cavernous ; trochlear nerve neurinomas arise almost exclusively from the cisternal segment of the nerve, while dumbbell tumors in the posterior and middle cranial fossae are relatively more common among abducens neurinomas . Almost all (9 of 10), cavernous neurinomas arise from the third nerve . At surgery, the identification of the nerve from which the tumor arose was possible in all cases of cisternal neurinoma, but only in half (7 of 14) of the cisternocavernous and cavernous neurinomas for which comment on the diagnosis was supplied . In the remainder, one of the nerves subserving eye movement was considered very likely to be the source on the clinical evidence and operative findings, the latter clearly ruling out the ganglion and trigeminal branches as possible sources .
Site and Growth Pattern
Cisternal neurinomas of the oculomotor nerve occupy the interpeduncular cistern and tend to remain medial, as a rule growing upwards into the retroinfundibular and suprasellar spaces, with possible compression of the third ventricle . Almost all neurinomas of the trochlear nerve occupy the cisterna ambiens in the middle incisural space, ventrolaterally to the midbrain and pons below the tentorium ; as they grow, they may extend above the tentorium or medially into the interpeduncular and prepontine cisterns . Only in one case of a small neurinoma found incidentally at necropsy [27] did the tumor lie on the dorsal surface of the midbrain, 1 .5 mm from the point at which the nerve emerged from the brain stem, in the zone of transition between the central and peripheral sheaths of the nerve . Cisternal neurinomas of the abducens nerve occupy the prepontine cistern, between clivus and pons, and tend to push laterally into the upper portion of the cerebellopontine angle . Cisternal neurinomas ranged in size from less than 5 mm to 7 cm . Cavernous neurinomas develop in the parasellar region, compressing or invading the blood vessels and cranial nerves of the cavernous sinus, may grow downward and laterally toward the middle cranial fossa, medially into the sellar cavity and sphenoidal sinus, forward into the orbit through the sphenoidal fissure, or upward into the sylvian sulcus . Cisternocavernous neurinomas extend into the posterior and middle cranial fossae ; those of the third nerve may grow above the sella turcica or into the lateral sulcus, causing compression and displacement of the third ventricle . Four tumors (25,29,45] were almost totally cav-
219
ernous and two retroclival [19,51] . Cisternocavernous and cavernous tumors were generally large . While all cisternal neurinomas are obviously intradural, cisternocavernous and cavernous neurinomas may rarely be extradural after perforating the dura mater of the cavernous sinus or on the floor of the middle cranial fossa 1291 . Clinical Features
The sex ratio of third, fourth, and sixth cranial nerve neurinomas was biased towards females (58% vs . 42%) . The mean age of patients was 43 .8 years, the median age 47 years (minimum 10 years, maximum 70 years) . The peak frequency was in the sixth (30 .5%) and in the fifth (25%) decades of life ; seven patients were under 20 years of age, and none was under 10 years of age . The tumor was found on postmortem examination in two subjects without symptoms with cisternal neurinomas of the third [40] and fourth [27] nerves . In most patients whose clinical history is known, the most frequent first symptom was a deficit of the nerve hosting the tumor : the third in 70% (14/20), the sixth in 60% (3/5), and the fourth in 44% (4/9) . Other initial symptoms were decreased visual acuity or hemiparesis in neurinomas of the third nerve ; ataxia of gait, paresthesias, or hemiparesis in those of the fourth nerve ; and symptoms of intracranial hypertension in those of the sixth nerve . If the decreased visual acuity in cavernous neurinomas is excluded, the nerve bearing the tumor was always the first symptomatic cranial nerve in neurinomas of the third and sixth nerves, while an isolated third nerve deficit is possible in cisternal neurinomas of the trochlear nerve . In cisternal neurinomas, the clinical history was short, under 2 years, in those of the fourth and sixth nerves and very long, 5 years or more, in those of the third . In cisternal neurinomas of the third and sixth nerves, the deficit of the host nerve was an isolated sign or was associated with signs of brain-stem compression, such as Weber syndrome in third nerve tumors, or with symptoms of intracranial hypertension in sixth nerve tumors . Neither trigeminal disturbances nor paresis of other nerves governing eye movements was present in any of the cases . Cisternal neurinoma of the third nerve seems able to cause deficit of the nerve earlier, when it is 5 mm or less in size [36,73] . On the other hand, in less than half of the nine symptomatic cisternal neurinomas of the trochlear nerve was the fourth nerve deficit the presenting symptom or a sign on admission . There were no trigeminal symptoms, but an oculomotor deficit was present in one-third of cases (in one of them, it was the only complaint) [18,45,68], and lastly, on admission one third of patients had no disturbance of eye movement at all [39,49,76] .
2 20
Surg Neurol 1992 ;38 :216-24
Third nerve involvement seems to be related to the medial progression of the tumor into the prepeduncular space or above the posterior clinoid . The absence or late onset of trochlear paralysis, even when the tumor is large, may be due to the length of the cisternal segment of this nerve [431, such that the tumor displaces and twists the nerve fibers instead of destroying them, and the signs of brain-stem compression may appear before or in the absence of paralysis of the nerve . Including our case, six patients with cisternal neurinoma of the trochlear nerve [7,39,49,68,76] presented signs of brain-stem compression, such as gait ataxia, and on the side opposite to the tumor, they had hemiparesis (all six), cerebellar disturbance of the limbs (four cases), and paresthesia with or without deficits of sensation (four cases) . Dysarthria and disturbance of taste were also noticed . Our patient and three others [7,39,49] presented a contralateral combination of hemiparesis and cerebellar limb signs, and three of them had paresthesias, as well . A similar combination of hemiparesis and cerebellar signs, the latter uncommonly contralateral to a nervous system lesion, was first reported by Fisher and Cole [16] in 1965 and named "ataxic hemiparesis" (15) . Since then, this syndrome, broadened to include other accompanying signs such as sensory disorders, gait ataxia, nystagmus, and dysarthria, was described in patients with various intra-axial lesions, principally ischemic and hemorrhagic, more rarely tumors [62], at the site where the pyramidal fibers run close to those of cerebrocerebellocerebral loop . The cerebellar symptoms are attributed to contralateral damage to the temporoparietopontine fibers in the posterior limb of the internal capsule, to the thalamic nuclei, to the thalamocortical projections [28,30,34,53,65], to the pontine nuclei, or to the pontocerebellar fibers [15] and, in the few reported cases of "midbrain ataxic hemiparesis" [4,23,241, as well as in Claude's mesencephalic syndrome [17], to impairment of crossed ascending dentatorubrothalamic fibers by an intra-axial lesion in the rostral midbrain . On the other hand, in cases of cisternal neurinoma of the fourth nerve, the ataxic hemiparesis syndrome is likely caused by extra-axial compression of the caudal midbrain . In fact, the radiological images and operative records show the tumor to be wholly or almost wholly below the tentorium, connected to the midbrain and pons . The compressive force of the mass thus seems to be exerted on the anterior lateral surface of the basis pedunculi (the middle segment of which houses the pyramidal tract and the lateral segment, the temporoparietooccipitopontine fibers [ 11,48]) and of the midbrain tegumentum (along which run the spinothalamic tract, the ascending tract of the trigeminus, and the medial lemniscus with its gustatory component [11]) .
Celli et al
The slow extrinsic compression exerted by the mass accounts for the long tract signs, for their mildness, and for their rapid regression after removal of the neurinoma ; furthermore, it accords with the absence of disturbances of conjugated gaze and of the oculomotor nerve . The homolateral combination of hemiparesis, cerebellar ataxia, and sensory disturbances in the presence of an extra-axial tumor at the tentorial notch is more strongly suggestive of a trochlear neurinoma than the actual nerve deficit, which in any case is missing in half of the patients with these signs . Further, these are the only cases traced in the literature of ataxic hemiparesis syndrome produced by a benign extra-axial infratentorial tumor . Of the six cisternocavernous neurinomas only one arising from the fourth nerve [451 presented a deficit of the nerve that gave rise to the tumor as the sole symptom . In almost all others, there was clinical or radiological evidence of intracranial hypertension, sometimes associated with contralateral hemiparesis, with disorders of other nerves of the cavernous sinus, or because of extension of the tumor into the suprasellar area and sylvian cistern, with aphasia and hemianopia . The 10 cavernous neurinomas, nine arising from the third nerve and one from the sixth, supplied two clinical patterns . One group of five patients [21,31,55,72,751, in whom the tumor was confined to the parasellar area, reached diagnosis with the deficit of the nerve hosting the tumor as an isolated sign, or sometimes with involvement of another of the nerves governing eye movement or of the ophthalmic nerve . Another group of five patients [3,29,35,61], with third nerve neurinoma and frequently with extension of the tumor into the posterior portion of the orbit, on admission presented exophthalmos and oculomotor nerve deficit, combined with more or less complete involvement of the other nerves of the superior orbital fissure and of the optic nerve (orbital apex syndrome) . In three of these patients, the first symptom was the oculomotor nerve deficit, and in the other two it was a decrease in visual acuity . The preoperative history was long, from 18 months to 20 years, and the radiographic findings were often striking, with widening of the superior orbital fissure or erosion of the floor of the middle cranial fossa. The difference in clinical pattern and in length of history points to early diagnosis in the first group and to an advanced stage of the disease and late diagnosis in the second .
Radiological Findings In cisternal neurinomas, the roentgenograms of the skull were generally negative . Cerebral angiography [7, 8,18,36,38,39,47,59,60,70,73,76,78,80] in large tumors revealed marked displacements of the superior cerebellar artery ; shifts of the posterior cerebral artery,
Neurinoma of Cranial Nerves
anterior inferior cerebellar artery, or basilar trunk were mild and less frequent . A tumor blush was seen in only one of the 15 cases studied . The skull radiography or CT scan of cisternocavernous and cavernous neurinomas showed circumscribed lesions of the sellar bones, clinoids, or tip of the petrous bone in half of the first group [29,45,51] and more conspicuous bone changes, such as widening of the superior orbital fissure and sometimes erosion of the floor of the middle cranial fossa, in some of the second group [3,29,35,61] . Shubiger et al [72] observed that erosion of the temporal fossa or the presence of a large tumor attachment to the floor of the middle cranial fossa rules out a neurinoma of the third, fourth, and sixth cranial nerves and clinches the diagnosis of trigeminal neurinoma ; this may well hold good for small neurinomas confined to the parasellar area but does not for larger tumors . Cisternocavernous [25,29] and cavernous 13,29 55,61,72,751 neurinomas studied by angiography commonly produced stretching and displacement downward and forward, and as a rule medially, of the intracavernous carotid artery, associated with upward and forward displacement of the supraclinoid carotid . In half of these neurinomas, the middle cerebral artery was stretched or elevated in the M1 segment . Pathological vessels were present in about half (4 of 10) patients . CT scan studies [3,7,8,18,19,21,25,29,31,38,45,47, 49,51,59-61,68,70,72,75,76,80] without contrast medium presented the variable pattern of neurinomas : low density, normal brain density, mixed normal and low density, or even high density . After contrast infusion, in all but one there was an increase in density, either uniform, patchy, or peripheral, very marked in some parasellar neurinomas . CT scan did not visualize a very small (3 X 4 mm) neurinoma causing third nerve palsy [36] . This possibility that neurinoma of the third nerve can become symptomatic when so small [36,73] that it could be undetected initially strongly indicates repeated neuroimaging studies in patients with acquired cryptogenetic oculomotor nerve deficit [1] . Almost never did clinical information and diagnostic imaging suggest a third, fourth, or sixth nerve tumor . In addition, in some cisternal neurinomas of the third and fourth nerves, CT scanning and angiography failed to dispel the doubt that the tumor might be intrinsic to the brain stem [8, 18, 47], something that magnetic resonance imaging (MRI) may do . In four patients [18,19,38,76], MRI depicted the lesion, which was extra-axial in all, as hyperintense on the T2-weighted image but isointense, hypointense, or hyperintense on the TI-weighted image . In several cisternocavernous and cavernous neurinomas, the preoperative diagnosis was meningioma (para-
Surg Neurol 1992 ;38 :216-24
221
sellar, of the lesser sphenoid wing, or of the cavernous sinus), because of the pathologial circulations imaged by angiography or the hyperdensity of the tumor on the CT scan before or after contrast infusion, Surgery In cisternal neurinomas of the third and fourth nerves, the surgical approach was subtemporal, transtentorial, frontotemporal, and rarely . suboccipital ; in two of the sixth nerve tumors, subtemporal and suboccipital approaches were used . Tumor removal was nearly always total ; in a few cases, fragments of pathological tissue adhering to blood vessels or to the brain stem were left behind . In cisternocavernous and cavernous neurinomas, the approach was subtemporal or frontotemporal in the former and frontotemporal in the latter . Only in about 50% of these was total removal reported, because the tumor tissue invaded the cavernous sinus or was firmly adherent to the carotid or middle cerebral artery . There was only one operative death, but almost all patients were left with deficit of the nerve from which the tumor arose . As a rule, the nerve was disrupted or sacrificed, its continuity being conserved in only two cases, cisternal neurinomas of the fourth [69] and sixth [9] nerves . In the case reported by Samii and by Samii and Draf [68,69], it was possible to dissect the tumor from the trochlear nerve and spare the uninvolved fascicles . The 50% chance of complete removal of parasellar neurinomas of the third, fourth, and sixth cranial nerves is similar to that reported for parasellar neurinomas of the fifth nerve in a recent review of the literature [74] . However it is possible that today's surgical techniques will make possible both total excision and anatomical preservation of the cranial nerves in the majority of paracavernous tumors . When disruption of one of the nerves subserving eye movement occurs during removal of a neurinoma, microsuture of the nerve should be attempted, because good functional results have been reported [13,20,32] ; in the case of the fourth and sixth nerves, the chances of functional recovery should be greater, since these nerves are purely motor, supply a single muscle, and are composed, in the majority of cases, of a single fascicle [57,58] . There was only one recurrence [77], 13 years after apparently total removal of a cisternal neurinoma of the third nerve [45], but there is no long-term follow-up information on the cases of incomplete tumor removal. Clinical Differences and Similarities Between Parasellar Neurinomas of the Third, Fourth, and Sixth Nerves and Those of the Fifth Nerve Boggam et al [7] suggested that intracranial neurinomas of the nerves governing eye movement were rare he-
222
Surg Neurol
Celli et al
1992 ;38 :216-24
cause they were probably mistaken for the more com-
regress after the removal of trigeminal neurinomas
mon trigeminal neurinomas . In fact, about one third of
[14,37,74,81] than after the removal of oculomotor,
patients with cisternocavernous and cavernous neurino-
trochlear, or abducens neurinomas.
mas present with paresthesias, pain, or more rarely, trigeminal hypesthesia, while some 50% of patients with neurinoma of the gasserian ganglion present a deficit of one or more of the nerves governing eye movement
References
[5,42,44,50,64,71,74] . However, in parasellar neurinomas of the third, fourth, and sixth nerves, the deficit of
1 . Abdul-Rahim AS, Savino PJ, Zimmerman RA, Sergort RC, Bosley TM . Cryptogenic oculomotor nerve palsy . The need for repeated neuroimaging studies . Arch Ophthalmol 1989 ;107 :387-90 .
the nerve that give rise to the tumor is always present
2 . Arseni C, Dumirrescu L, Costantinescu A . Neurinomas of the rrigeminal nerve . Surg Neurol 1975 ;4 :497-503 . 3 . Bataille B, Muckensturm B, Roualdes G, Maissin F, Deglaire B, Desbordes JM . Neurinome du nerf oculomoteur . A propos d'un cas . Neurochirurgie 1987 ;33 :405-7 .
on examination, and this nerve is always the first symptomatic cranial nerve, if the visual deficit in cavernous neurinomas is excluded . The trigeminal symptom, when observed, is confined to the first division, is never the first symptom, is never isolated, and is hardly ever a deficit . In neurinomas of the gasserian ganglion, by contrast, a third or fourth nerve deficit never seems to have been reported as an isolated symptom and is very rarely (3%) reported as the first symptom of the disease [741, Paresis
of the abducens nerve, although a common symptom, being the first symptom in one fifth of cases and the second most frequent on admission [741, is rarely an isolated sign or symptom of onset, followed by a trigeminal disturbance confined to the first division [14,26,37,
50,54,64,81] . Among middle fossa neurinomas that produce exophthalmos (rarer now because of early diagnosis), there are no clinical differences between those arising from the third nerve and those arising, with an incidence of
11%-17% [12,50,74], from the gasserian ganglion [2,5,6,10,41,46,52,7 11 and more rarely from the intracranial ophthalmic division [44,641 . They usually have the following points in common : a long preoperative history, a possible third nerve deficit or reduction of visual acuity at onset, trigeminal disorders often absent or limited to the first branch, and on admission a more or less complete clinical-radiological pattern of orbital apex syndrome . At an advanced stage of the disease, the angiographic changes in the parasellar carotid artery do not differ between neurinomas of the third nerve and those of the gasserian ganglion . In small tumors, however, distinctive points to look for are elevation of the supraclinoid intradural carotid artery, with enlargement of the upper curve of the carotid siphon, for the third nerve neurinoma and displacement and stretching of the extradural ganglionic carotid artery for neurinoma of the gasserian ganglion
[63,66,791 . At operation, parasellar neurinomas of the third, fourth, and sixth nerves usually appear to be intradural, while those of the gasserian ganglion are extradural . Lastly, the preoperation deficit of eye movement, especially in the case of the sixth nerve, is more likely to
4 . Bendheim PE, Berg BO . Ataxic hemiparesis from a midbrain mass . Ann Neurol 1981 ;9 :405-6 . 5 . De Benedettis G, Bernasconi V, Ettorre G . Turnouts of the fifth cranial nerve . Area Neurochir (Wien) 1977 ;38 :37-64 . 6 . Bernasconi V, Papo 1, Beduschi A, D'Andrea F . I neurinomi del trigemino. Chirurgia 1957 ;12 :405-26 . 7 . Boggam JE, Rosenblum ML, Wilson CB . Neurilemmoma of the fourth cranial nerve . Case report . J . Neurosurg 1979;50 :519-21 . 8 . Broggi G, Franzini A . Value of serial stereotactic biopsies and impedance monitoring in the treatment of deep brain tumours . J Neurol Neurosurg Psychiatry . 1981 ;44 :397-401 . 9 . Chen BH . Neurinoma of the abducens nerve . Neurosurgery 198 1 ;9 :64-6 . 10 . Cohen I . Tumours involving the Gasserian ganglion . J Nerv Menr Dis 1933 ;78 :492-9 . 11 . Crosby EC, Humphrey T, Laner EW . Correlative anatomy of the nervous system . New York : Macmillan, 1962 :731 . 12 . Dany A, Pefferkorn JP, Vallat JN, Loubet R, Maudoux M . Ncurinome du ganglion de Gasser a developpement temporal . Neurochirurgie 1970 ;4 :349-56. 13 . Deruty R, Guyotat J, Mottolose C, Bady B, Girard Madoux M, Vigherto A, Vila A . Recuperation partielle du nerf moteur oculaire common apres section puis reparation au tours de Fexerese dune tumeur. Neurochirurgie 1988 ;34 :287-92 . 14. Findler G, Feinsod M, Sahar A . Trigeminal neurinoma with unusual presentation . Report of a case with trigeminal somatosensory-evoked response. Surg Neurol 1983 ;19 :351-3 . 15 . Fisher CM . Ataxic hemiparesis . A pathologic study . Arch Neural 1978 ;35 :126-8 . 16. Fisher CM, Cole M . Homolateral ataxia and crural paresis : a vascular syndrome . J Neurol Neurosurg Psychiatry 1965 ; 28 :48-55 . 17 . Fog M, Hein-Sorensen 0 . Mesencephalic syndromes . In : Vinken PJ, Bruyn GW, eds : Handbook of clinical neurology-localization in clinical neurology, vol 2 . Amsterdam : North-Holland, 1969 :272-85 . 18. Garen PD, Harper CG, Teo C, Johnston IH . Cystic schwannoma of the trochlear nerve mimicking a brain-stem tumor . Case report. J Neurosurg 1987 ;67 :928-30 . 19. Ginsberg F, Peysrer RG, Rose WS, Drapkin AJ . Sixth nerve schwannoma: MR and CT demonstration . J Comput Assist Tomogr 1988 ;12 :482-4 . 20. Grimson BS, Ross MJ, Tyson G . Return of function after intracranial suture of the rrochlcar nerve . Case report . J Neurosurg 19K61 191-2 . 21 . Hausman ML, Hoover ED, Peysrer RG . Sixth nerve neuroma in the cavernous sinus : CT features . Case report. J Comput Assist Tomogr 1986 ;10x030-2 .
Neurinoma
of Cranial
Nerves
22 . Hasegawa H, Bitch S, Otsuki H, Fujiwara M, Yamamoto T, Kobayashi Y . Catecholamine-secreting malignant schwannoma in a patient with multiple intracranial aneurysms . Case report . J Neurosurg [984 ;60 :1089-94 . 23 . Helweg-Larsen S, Larsson H, Henriksen 0, Sorensen PS . Ataxic hemiparesis : three different locations of lesions studied by MRI . Neurology 1988 ;38 :1322-4 .
Surg Neurol 1992 ;38 :216-24
2 23
45 . Leunda G, Vaquero J, Cabezudo J, Garcia-Uria J, Bravo G . Schwannoma of the oculomotor nerve . Report of four cases . J Neurosurg 1982 ;57 :563-5 . 46 . Loew F, Tennis W . Klinik and Behandlung der Neurinome des Nervus trigeminus . Zentralbl Neurochir 1954 ;14 :32-41 . 47 . Lunardi P, Rocchi G, Rizzo A, Missori P . Neurinoma of the oculomotor nerve. Clin Neurol Neurosurg 1990 ;92-4 :333-5 .
24 . Hershkowitz N, Bergey GK, Josyln J, Evans D . Isolated midbrain lesion resulting from closed head injury : a unique presentation of ataxic hemiparesis . Neurology 1989 ;39 :452-3 .
48 . Maria OS, Angevine JB, Locke S . Topographical organization of the lateral segment of the basis pedunculi in man . J Comp Neurol 1962 ;118 :165-83 .
25 . Hiscott P, Simon L: An unusual presentation of neurofibroma of the oculomotor nerve . J Neurosurg 1982 ;56:854-6 .
49 . Maurice-Williams RS . Isolated schwannoma of the fourth cranial nerve : case report. J Neurol Neurosurg Psychiatry 1989 ; 52 :1442-3 .
26 . Hitchon PW, Graf CJ, McCabe BE, Namba K . Trigeminal neurilemmoma presenting as a sphenoid sinus mass . Surg Neurol 1979 ;11 :305-7 . 27 . Ho KL . Schwannnmaof the trochlear nerve . Case report j Neurosurg [981 ;55 ;132-5 . 28 . Hommel M, Gaio JM, Pollak P, Borgel F, Perret J : H€mipar€sie ataxique par lacune rhalamique . Rev Neurol (Paris) 1987 ;143 : 602-4 . 29 . Huber A . Das Okulomotoriusneurinom . Min Monatsbl Augenheilkd 1978 ;172 :627-35 . 30 . Iragui VJ, McCurchen CB . Capsular ataxic hemiparesis . Arch Neurol 1982 ;39 :528-9 . 31 . Ishige N, Ito L, Saeki N, Oka N . Neurinoma Nith intrasellar extension : a case report . No Shinkei Geka 1985 ;13 :79-84 (in Japanese). 32 . Iwabuchi T, Suzuki M, Nakaoka T, Suzuki S . Oculomotor nerve anastomosis . Neurosurgery 1982 ;10 :490-1 . 33 . Jefferson G . Trigeminal neurinomas with some remarks on malignant invasion of the Gasserian ganglion . Proc Congr Neurol Surg 1955 ;1 :11-54 . 34 . Jokelainen M, Pilke A . Ataxic hemiparesis . Arch Neurol [983 ;40 :326 (letter) . 35 . Kan T, Kouki T, Yamada H, Hirakawa K . Neurinoma of the oculomotor nerve . Case report . Rinsho Shinkeigaku 1976 ;16:540 (in Japanese) . Cited in : Katsumata Y, Maehara T, Noda M, Shirouzu 1 . N eurinoma of the oculomotor nerve : CT and MR features . Case report. J Comput Assist Tomogr 1990 ;14 :658-61 . 36 . Kansu T, Ozcan OE, Ozdirim E, Cool B, Gurcay O . Neurinoma of the oculomotor nerve . Case report . J Clin Neuro Ophthalmol 1982 ;2 :271-2 . 37 . Katoh M, Kadoya S, Emori T, Kwak R . Trigeminal neurinoma presenting abducens nerve palsy as initial symptom : a report of two cases . No Shinkei Geka 1985 ;13 :555-60 (in Japanese). 38 . Katsumata Y, Maehara T, Noda M, Shirouzu L Neurinoma of the oculomotor nerve : CT and MR features . Case report. J Compur Assist Tomogr 1990 ;14 :658-61 . 39 . King JS . Trochlear nerve sheath tumor . Case report. J Neurosurg 1976 ;44 :245-7 . 40 . Kovacs W . Ueber ein solirares Neurinom des Nervus oculomotorius . Zentralbl AlIg Pathol 1927 ;40 :518-22 . 41 . Kraft H. Bench uber einen Fall von Neurofibromatose mit orbitookularen Symptomen and sekundaren Sellaveranderungen . Klin Monatsbl Augenheilkd 1970 ;156 :112-8. 42 . Krayenbuhl H . Primary tumors of the root of the fifth cranial nerve : their distinction from tumors of the gasserian ganglion . Brain 1936 ;59 :337-52 . Lang J . Uber Ban, Lange and Gefassbeziehungen der "zentralen" and "peripheren" Strecken der intrazisternalen Hirnnerven . Zentralbl Neurochir [982 ;43 :217-55 . 44 . Lesoin F, Rousseaux M, Villetre L, Aurricque A, Dhellemmes P . Pellerin P, Vaneecloo JM, Leys D, Jomin M . Neurinomas of the trigeminal nerve . Acts, Neurochir (Wien) 1986 ;82 :118-22 .
50 . McCormick PC, Bello JA, Post KD . Trigeminal schwannoma . Surgical series of 14 cases with review of the literature . J Neurosurg 1988;69 :850-60 . 51 . Mehta VS, Singh RVP, Misra NK, Choudhary C . Schwannnmaof the oculomotor nerve . Br J Neurosurg 1990 ;4 :69-72 . 52 . Mello LR, Tanze A . : Some aspects of trigeminal neurinomas . Neuroradiology 1972 :4 :215-21 . 53 .
Man
E, Yamadori A, Kudo Y, Tabuchi M . Ataxic hemiparesis from small capsular hemorrhage. Computed tomography and somatosensory evoked potentials . Arch Neurol 1984 :41 :1050-3 .
54 . Morniroli G . Das Trigeminusneurinom . Schweiz Arch Neurol Neurochir Psychiatr 1970 ;107 :17-86 . 55 . Nagamune A, Kuwana N, Kuwahara R. Neurinoma of the oculomotor nerve . Case report. Rinsho Shinkegaku 1974 ;11 :195 (in Japanese) . Cited in : Nogami K, Nishijima M . Endo 5, Takaku A . Neurinoma of the oculomotor nerve . Case report . No Shinkei Geka 1986 ;14 :1237-41 (in Japanese) . 56. Nager GT . Acoustic neurinomas . Pathology and differential diagnosis . Arch Otolaryngol 1969 ;89:252= 9 . 57 . Nathan H, Goldhammer Y . The rootlets of the rrochlear nerve ; anatomical observations in human brains_ Acra Anar 1973 ;84 : 590-6 . 58 . Nathan H, Ouaknine G, Kosary JZ . The abducens nerve : anatomical variations in its course . J Neurosurg 1974 ;41 :561-6 . 59 . Nehls DG, Sonntag VKH, Murphy AR, Johnson PC, Waggener JD . Fibroblastic tumor of the abducens nerve . Case report . J Neurosurg 1985 ;62 :296-99 . 60 . Nogami K, Nishijima M, Endo S, Takaku A . Neurinoma of the oculomotor nerve . Case report . No Shinkei Geka 198G14 : 1237-41 (in Japanese) . 61 . Okamoto S, Handa H, Yamashira J . Neurinoma of the oculomotor nerve . Surg Neurol 1985 :24 :275-8 . 62 . Orgogozo JM, Bogousslavsky J . Lacunar syndromes. In : Vinken P3, Bruyn GW, Klawans HL, eds : Handbook of clinical neurology-vascular diseases, part IT, vol 54 . Amsterdam : Elsevier, 1989 :235-69 . 63 . Palacios E, MacGee EE . The radiographic diagnosis of trigeminal neurinomas . J Neurosurg 1972 :36:153-6. 64 . Pollack F . Sekhar LN, Jannerta P3 . Janecka IP . Neurilemomas of the trigeminal nerve . J Neurosurg 1989 ;70 :737 -45 . 65 . De Renzi E, Nichelli P, Crisi G . Hemiataxia and crural hemiparesis following capsular infarct J Neurol Neurosurg Psychiatry 1983 ;46 :561-3 . 66 . Ruherti R, Galligiont F, Carreri A . Considerations radiologiques clans les neurinomes du ganglion de Gasser . Acres Radiol Diagn 1966 ;5 :465-9 . 67 . Russel DS, Rubinstein I .J . Pathology of tumors of the nervous system, 4th ed . Edinburgh : Edward Arnold, 1977 :44868 . Samii M . Intracranial compression of the third, fourth and sixth cranial nerves by tumors . In : Samii M . Jannetta PJ, eds : Cranial
224
Surg Neurol 1992 ;38 :216-24
nerves: anatomy, pathology, pathophysiology, diagnosis, treatment. Berlin : Springer-Verlag, 1981 :241-8 . 69. Samii M, Draf W. Surgery of the skull base . Berlin : SpringerVerlag, 1989 :335-7 . 70 . Satoh K, Saitoh S, Satoh K, Yamada K, Nakai A. Neurinoma of the oculomotor nerve causing ophthalmoplegic migraine . Med Consult New Remed (Tokyo) 1985 ;22 :1062-6 (in Japanese) . 71 . Schisano G, Olivecrona H . Neurinomas of the gasserian ganglion and trigeminal root. J Neurosurg 1960 ;17 :306-22 . 72 . Schubiger 0, Valavanis A, Hayek J, Dabir K. Neuroma of the cavernous sinus . Surg Neurol 1980 ;13 :313-6. 73 . Shuangshoti S, Neurilemmoma of the oculomoror nerve . Br J Ophthalmol 1975 ;59 :64-6. 74 . Sindou M, Pelissou 1 . Trigeminal neurinomas . A special type of cavernous sinus tumors . In : Dolenc VV, ed : The cavernous sinus . Vienna: Springer-Verlag, 1987 :355-76 . 75 . Takano S, Endo M, Miyasaka Y, Yada K, Ohwada T, Takagi H . Neurinoma of the oculomotor nerve . Case report. Neurol Med Chir (Tokyo) 1990 ;30 :132-6 .
Celli et al
76. Tokuriki Y, Yamashita J, Kikuchi H, Asaro R, Handa H . Trochlear nerve neurinoma. Case report . Neurol Med Chir (Tokyo) 1988 ;28 :70-3 . 77 . Vaquero J, Martinez R, Salazar J . Suprasellar recurrence of third nerve neurinoma. J Neurosurg 1985 ;62 :317 (letter). 78. Wakabayashi S, Misawa I, Uno A, Hananouchi M . Schwannoma of the oculomotor nerve with a cerebral aneurysm . Case report. Rinsho Shinkeigaku 1978 ;18 :433 (in Japanese). Cited in : Katsumata Y, Maehara T, Noda M, Shirouzu 1 . Neurinoma of the oculomotor nerve : CT and MR features . Case report. J Comput Assist Tomogr 1990 ;14 .658-61 . 79. WestbergG .Angiographicchanges inneurinomaofthetrigeminal nerve . Acta Radial Diagn 1963 ;1 :513-20. 80. Yamamoto M, Jimbo M, Ide M, Kubo O . Trochlear neurinoma. Surg Neurol 1987 ;28 :287-90 . 81 . Yamashita J, Asato R, Handa H, Nakao S, Ogata M . Abducens nerve palsy as initial symptom of trigeminal schwannoma . J Neurol Neurosurg Psychiatry 1977 40 :1190-7 . 82 . Zulch KJ . Brain tumors : their biology and pathology, 3rd ed . Berlin : Springer-Verlag, 1986 :704 .
