NOVEMBER,

SCHWANNOMAS NERVOUS Downloaded from www.ajronline.org by 45.32.65.22 on 06/21/16 from IP address 45.32.65.22. Copyright ARRS. For personal use only; all rights reserved

By

J. DANZIGER, S. BLOCH,

D.M.R.D.

D.M.R.D.

R.C.P.

UNIV.

EDIN.,

OF

LOND.,

and

H.

THE SYSTEM*

CENTRAL

R.C.S. ENG., M.MED. PODLAS, D.M.R.D.

JOHANNESBURG,

SOUTH

5975

(RAD.D.)

R.C.P.

UNIV. CAPE TOWN, LOND, R.C.S. ENG.

AFRICA

ABSTRACT:

Isolated schwannomas may occur in many different situations within the central nervous system. Most neurilemmomas are benign, and enucleation after longitudinal dissection of the nerve will usually affect a cure. It is for this reason that the roentgenological appearances should be appreciated and this diagnosis considered so as to attempt total surgical removal. pharyngeal and other motor nerves are usually involved in the multiple manifestation of von Recklinghausen’s disease, but as sites for solitary schwannomas are cxtremely rare.

I SOLATED eight percent

schwannomas form of all primary intracranialabout tumors, usually occur during the middle years of life, and are twice as common in females as in males.9”3 They are extremely rare in childhood8 and, as in an adult, the acoustic nerve is the site of predilection.3 Neurinomas of the spinal cord are relatively common, accounting for about 30 percent of all spinal tumors.7 The purpose of this communication is to report the roentgenographic appearances of schwannomas occurring in the central nervous system. CRANIAL

NERVE

This tumor has a affect sensory nerves segment of the root the pia mater. The frequently involved, the tumor has been the trigeminal nerve.

B

projection,

From the Department

of Radiology,

non-filling Princess

Nursing

NEURINOMAS

Acoustic

neurinomas account for apeight percent of all intracranial tumors and for 8o percent of tumors of the cerebello-pontine angle.’3 Most, but not all, acoustic neurinomas originate within the internal auditory canals, presumably at the junction between the neunilemma! sheath arising from the peripheral ganglia and the neuroglial fibers extending peripherally from the brain stem. The patient usually presents with unilateral sensonineural hearing loss, followed by slight dizziness or imbalance and less frequently by true vertigo.’7 Roentgenographic evaluation of the internal auditory canal is best performed by

tendency to selectively and arises on a distal after it has penetrated acoustic nerve is most although on occasions observed arising from The vagus, glosso-

demonstrating

ACOUSTIC

proximately

INVOLVEMENT

FIG. I . (A) Tomography of the internal auditory canal ( I ) with shortening of its posterior

oblique

(A)

meatus wall. (B)

demonstrating

widening

of the

Posterior of the left internal

fossa cisternogram, auditory canal

Home,

South

Johannesburg,

692

Africa.

left

shoot (

).

internal

through

auditory

prone!

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VOL.

No.

525,

Schwannomas

3

of the

Central

Nervous

System

693

p.-

FIG.

tion

2.

(A)

Vertebral

angiogram,

of the left anterior

demonstrating

a mass

anteroposterior

inferior superolaterally

projection

with

cerebellar

artery ( I ) around in the cerebello-pontine

tomography where : (a) erosion of the cortical line surrounding the lumen of the canal; (b) widening by i to 2 mm of any portion of the internal auditory canal in comparison to the corresponding segment of the opposite side; (c) shortening of the posterior wall by at least 2 to 3 mm; and (d) shorten-

ing more

of

subtraction,

the mass. angle. the

when

demonstrating

(B) Posterior

crista

compared

falciformis

with

marked elevacisternogram,

fossa

by

the

i

normal

mm

or side

(Fig. i1) may be observed. Study of the cerebello-pontine cistern and of the subarachnoid space within the internal auditory canal is performed by vertebral angiography (Fig. 2d), air studies,

J’

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694

Danziger,

S. Bloch

and

FIG. 5. strating bone

H.

Podlas

NOVEMBER,

Skull, anteroposterior projection, destruction of the apex of the left

5975

demonpetrous

( 1).

ment

in the internal auditory meatus (Fig. In the study of the internal auditory canal with positive contrast medium, incomplete filling may occur due to anatomic variants or conditions other than a tumor. These include the size of the canal, which varies from 2 to 10 mm with an average of 4.5 tO 5 mm, shortening of the meningeal sleeve cul-de-sac, and viscosity of the myodil, when the canal is relatively small, since the size of the neurovascular bundle remains constant.’6 I f pneumoencephalography or ventniculography is performed, this will demonstrate the size of the tumor within the cerebello-. IB).

FIG. 4. Myodil ventriculogram, posterior projection, showing aqueduct and partially filled the right.

brow up anterodisplacement of the fourth ventricle to

and posterior fossa cisternography (Fig. iB). When a mass is present, its vertical diameter and extension along the posteromedial aspect of the petrous bone can be evaluated as well as the extent of involve-

L

6. Left

forward physeal

I angiogram, and medial artery ( I).

displacement

(

Anteroposterior

and

of the

portion

ganglion

I

..) lateral of the

projections, carotid

siphon.

demonstrating Note

the

downward, meningohypo-

VOL.

No.

125,

Schwannomas

3

of the

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pontine angle, by the extent that stem is displaced with related (Fig. 3, ii and B; and 4). (B) TRIGEMINAL

These

are rare

Central

Nervous

System

695

the brain rotation

TUMORS

and

comprise only 0.2 pertumors and occur most commonly in the fourth decade.’4 They originate in the gassenian ganglion or tngeminal nerve root and therefore will be located in Meckels’ cave or in the cenebellopontine angle. When the tumor increases in size, it may become dumbell in shape and will then be located in both the middle and posterior cranial fossae. These tumors are well circumscribed, grow very slowly and consequently reach a large size before of intracranial

cent

causing

sufficient

symptoms

to

require

FIG. 7. Carotid angiogram, lateral arterial showing elevation and posterior displacement the proximal portion of the middle cerebral by a mass. Note the meningohypophyseal tery ( I ) supplying the tumor.

in-

vestigation. Their although depending

symptomatology is fairly typical the manifestations may be varied upon the site ofonigin and direction of spread of the tumor.’2 Plain roentgenograms of the skull may show destruction of the anteromedial portion of the petrous apex which is smooth and well delineated (Fig. 5). With extension of the tumor into the middle cranial fossa, carotid angiography will demonstrate that the ganglial part of the siphon (which is normally located cxtradurally) is displaced forward, downward

and

medially

also

be

group

(Fig.

6, 1

elevation

of

of arteries,

phase, of artery ar-

and B). There may the middle cerebral

stretching

of the

anterior

basal ofRosenthal. A tumor circulation may be evident, usually deep within the middle fossa supplied by the tentonial branch of the meningo-hypophyseal artery (Fig. 7). Spread of tumor into the posterior cranial fossa will be shown by elevation of the posterior cerebral artery, and destruction choroidal

artery,

and

of the

elevation

vein

of

the

anteromedial

portion

of the

petrous

apex.

w .

I

. -

.

.

..

S

.

.

.

.

-.

.

.

.5

*

..

S

S

.

..

, .

.

.. S

.

. .

.

.

.

S

.

. S

4

.

S

. .

S

.

S S S

A -

FIG.

--

=

8. Brain

__.

scan,

-

#{149}

-

.#{149}

S

#{149} S

-‘

..

.

.

kt,

fl

#{149}

#{149}

.5

. = .,

___._-

.

S

the

and (B) lateral projections, anterior part of the middle

. S

S



demonstrating cranial

fossa

.

.

-

I

---s-

(A) anteroposterior uptake within

.

#{149}

. S

.

#{149}

..

an area

( I).

#{149}

S

#{149}

S of increased

J.

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696

Danziger,

S. Bloch

and

H.

Podlas

NOVEMBER,

1975

rounding the area ofcalcification suggesting that the latter lay in the pes hippocampi (Fig. io). Right carotid angiography demonstrated slight asymmetry of the middle cerebral arteries, the knee of the right middle cerebral artery being displaced medially. No tumor circulation was demonstrated. The mass was removed surgically from the temporal lobe and histologically proved to be a schwannoma. SCHWANNOMA

Fio.

9. Tomography of middle cranial fossa, lateral projection, demonstrating an area of irregular calcification in the right temporal region ( ).

Radioactive brain scanning may demonstrate the situation of the tumor by an area of increased uptake lying deep within the middle cranial fossa (Fig. 8, 4 and B). INTRACEREBRAL

SCHWANNOMA

Parenchymatous schwannomas of the brain are rare.’8 As far as we are aware, only two other documented reports of intracerebral schwannomas have been published.6” Our patient complained of episodes of uncontrollable behaviour of which he had no recollection. Roentgenograms of the skull showed an area of calcification in the right temporal region and slight enlargement of the right middle cranial fossa. Tomography confirmed the presence of a well defined area or irregular calcification in the right middle fossa (Fig. 9). Pneumoencephalography showed a cap of air sur-

FIG. 30. Pneumoencephalogram, right temporal horn

( I ) located

showing

above

an area

in the pes hippocampi.

air

in

of calcification

the

ARISING PITUITARY

WITHIN

THE

FOSSA

To the best of our knowledge, a schwannoma arising within the pituitary fossa has not been previously reported. This patient presented with a history of headaches and progressive blindness. This tumor produced destruction of the pituitary fossa, extending upward to dcvate and encroach onto the optic nerves and downwards into the sphenoid sinus and nasopharynx. Lateral extension of the tumor produced occlusion of both carotid arteries by direct involvement as well as destruction of the right petrous temporal bone (Fig. i I ; and i 2, ii). The tumor was surgically visualized and histologically proved. ORBITAL

A schwannoma

bit

is considered

SCHWANNOMAS

occurring within the orto be a rare tumor.5 This

FIG. I I . Pneumoencephalogram, intrasellar mass extending Note the destruction of literation of the sphenoid

the nasopharynx

( I).

demonstrating an superiorly (open arrow). the pituitary fossa, obsinus and extension into

VOL.

525,

No.

3

Schwannomas

of the

Central

Nervous

System

697

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S

FIG. I 2. Bilateral carotid angiogram, lateral arterial phases, demonstrating occlusion of both internal carotid arteries as far as the carotid siphon. The intracranial circulation on the left is filling via the vertebrobasilar system by means of collateral circulation in the neck.

is a localized, nerve sheath distinctive exophthalmos

encapsulated, tumor growing clinical features. and blurring

usually benign slowly without It can cause of vision by

pressure may

be

larged strated

on the optic nerve.’0 very vascular, supplied ophthalmic artery, and on carotid angiography

This tumor by an enwell demon(Fig. 13, 4

A FIG. 13. Selective left internal carotid onstrating an enlarged ophthalmic

bit(1).

angiogram

artery

with

supplying

subtraction,

a vascular

(A)

tumor

arterial

within

(B) venous phases, demthe superior part of the or-

and

J.

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698

Danziger,

S. Bloch

and

H.

14. Lu ,.r spine, (A) lateral and (B) anteropostenior prc posterior margin of a lumbar vertebra produced by a schwannoma Note that the adjacent pedicle is thinned inferiorly and medially.

and B). Venography may aid in defining the situation of the mass lesion within the orbit, but gives no indication as to its pathology. If the intra-orbital pressure is significantly elevated, there may be nonvisualization of the superior ophthalmic

FIG.

15. Myelography

in three

patients,

showing

Podlas

NOVEMBER,

ections, demonstrating originating within

the

scal spinal

)ing of canal (

5975

I).

vein on the involved side. Recurrence of the tumor after total cxcision is uncommon but does occur. This is considered to be due to residual elements of tumor remaining after surgery rather than due to malignant change.

the

typical

cap

deformity

of intradural

neurinomas.

VOL.

525,

No.

Schwannomas

3

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SPINAL

of the

Central

Nervous

System

699

NEURINOMAS

These tumors may be situated at any point along the long axis of the spinal cord or cauda equina. Since these tumors originate from the nerve sheath, they may be situated extradurally, intradurally, or have an element which is situated both extra and intradurally. ( A)

INTRADURAL

NEURINOMAS

These are in direct contact with the contrast medium. Hence, they are sharply outlined by the dye as clear cut cap defects (Fig. ii). This is their most common characteristic feature.’ As they arise from the

FIG. 17. Cervical demonstrating

dumbbell larged

1”

-.

demonstrating contrast column

an extradural at T2 ( I).

displacement

schwannoma intervertebral

at foramen

oblique projection, component of

C3/C4.

(

Note

the

a

en-

).

roots, they tend to lie to one side of the midline and displace the cord to the contralateral side. Those that occupy a more central position during their growth, either in front of or behind the spinal cord, displace the cord in a sagittal direction. This results in an anteroposterior compression of the cord, causing an increase in its coronal diameter. The block produced by such a tumor will be indistinguishable from that produced by an intramedullary tumor in the anteroposterior projection. A lateral projection will, however, reveal the relationship of the tumor to the spinal cord. The symptomatology varies according to nerve

jection, of the

myelogram, the intradural

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700

J.

Danziger,

S. Bloch

and

H.

Podlas

NOVEMBER,

1975

the cauda equina if eccentrically situated. If the tumor is centrally located a central cap-shaped defect is produced. Neurinomas in this region attain a large size and produce featureless total blocks.4 (B)

EXTRADURAL

NEURINOMAS

Like other extradural tumors, these displace the arachnoid from the pedicles, producing a lateral indentation on the contrast column with or without complete obstruction, depending on the size of the tumor (Fig. i6). ( C) INTRA AND EXTRADURAL

FIG. I 8. Vertebral angiogram, lateral demonstrating anterior displacement bral artery by a schwannoma.

projection, of the verte-

the situation of the tumor in the spinal canal.’ Plain roentgenograms are helpful only in approximately 30 percent of cases.2 The most frequent primary roentgenographic finding is enlargement of the adjacent intervertebral foramen due to pressure erosion produced by growth of the tumor along the axis of the root through the foramen. This area of constriction at the foramen causes the tumor to be dumbbell in shape, and thus produces pressure erosion of the adjacent bone. Widening of the spinal canal with indentation into the dorsal aspect of the related vertebral body may also be observed (Fig. 14, 4 and B). Diagnostic accuracy is in the region of 98 percent with myelography.2 The myelographic appearances will vary depending upon whether the tumor is situated extraor intradurally : intradural tumors situated below the level of the spinal cord may cause displacement of the nerve roots of

NEURINOMAS

The myelographic pattern is influenced by the size of each component of the dumbbell tumor (Fig. 17). The intradural portion generally produces the typical cap deformity with displacement of the spinal cord. The extradural part can be discerned only if there is a lateral indentation on the side of the tumor in addition to the cap defect. This will be evident ifthe extradural part is of sufficient size and is intraspinally located. When the schwannoma is situated in the cervical region, vertebra! angiography is valuable in defining the extent of the antenor and medial displacement of the yentebral artery by the tumor, since this may not be evident from the size of the enlarged intervertebral foramen (Fig. i 8). J. Danziger, Princess Esselen

M.D. of Radiology Nursing Home

Department

Street

Hillbrow

2001

J ohannesburg,

South

Africa

REFERENCES I.

BALAPARAMESWARA

and of

SUJATHAMMA, fifty

surgical

RAO, M. S., DINAKAR, I., Y. Spinal neuninoma: study cases. Internat. Surg., I 970, 5sf,

410-414. 2.

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localization of tuAM. J. ROENTGENOL., RAD. THERAPY, 1938, 40, 540-544. CRAIG, W. M., DODGE, H. W., and Ross, P. J. Acoustic neuromas in children: report of two cases. 7. Neurosurg., 1954, II, o-o8. DINAKAR, I., and BALAPARAMESWARA RAO, M. S. CAMP,

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of 57,

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of the

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fifth

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Downloaded from www.ajronline.org by 45.32.65.22 on 06/21/16 from IP address 45.32.65.22. Copyright ARRS. For personal use only; all rights reserved

DUKE-ELDER, S. Textbook of Ophthalmology. Henry Kimpton, London, 1952, pp. 6. GIBSON, A. A. M., HENDRICK, E. G., and CONEN, P. E. Intracerebral schwannoma: report ofcase. 7. Neurosurg., 1966, 24, 552-554. 7. JACOBS, R. L., and BARMADA, R. Neurilemoma: review of literature with six case reports. A.M.A. Arch. Surg., 1971, 102, 8i-i86. 8. MATSON, D. D. Neurosurgery of Infancy and Childhood. Second edition. Charles C Thomas, Publisher, Springfield, Ill., i 969. 9. MINCKLER, J. Supporting cell tumors of peripheral nerves. In: Pathology of the Nervous System. Edited by J. Minckler. McGraw-

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7. Ophth., 1970, 5i1, 206-207. NEW, P. F. J. Intracerebral schwannoma: report. :i. Neurosurg., I 972, 36, 795-797. OLIVE, I., and SvIEN, H. J. Neurofibromas

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RUSSELL, D. S., and RUBIN5TEIN, L. J. Pathology of Tumours of the Nervous System. Third edition. Edward Arnold & Company, London, 1971. ScHIsoNo, G., and OLIVECRONA, H. Neurinomas of gasserian ganglion and trigeminal root. 7. Neurosurg., I 960, 17, 306-322. SHAPIRO, J. H., OCH, M., and JACOBSON, H. G.

Differential

diagnosis of intradural (extraand extradural spinal canal tumors. Radiology, 1961, 76, 718-732. VALVASORRI, G. E. Abnormal internal auditory canal: diagnosis of acoustic neuromas. Radiology, 1969, 92, 499-459. VALVASORRI, G. E. Diagnosis of acoustic neuromas. Otolaryng. C/in. North America, I 973, medullary)

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17.

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I I.

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484-505.

730-734.

5.

Hill

Nervous

VAN

391-400.

case of

J.,

M.

RENSBURG,

DANZIGER,

J., and

temporal lobe schwannoma. chiat., 1975,38,

epilepsy

7. Neurol., 703-709.

M.

PROCTOR,

ORELOWITZ,

due

M.

S.

F.,

S. Case

of

to an intracerebral Neurosurg.

& Psy-

Schwannomas of the central nervous system.

Isolated schwannomas may occur in many different situations within the central nervous system. Most neurilemmomas are benign, and enucleation after lo...
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