Ependymal cyst of the spinal cord Case report
JAMES A. MOSSO, M.D., AND M. ANTHONY VERITY, M.D. Divisions of Neurosurgery and Neuropathology, The Center for the Health Sciences, University of California at Los Angeles, Los Angeles, California
A case with extramedullary ependymal cyst of the spinal cord is presented. The clinical, operative, and pathological findings are discussed and a review of previous cases and a nosologic classification of ependymal lined cysts given. KEY WORDS
9
ependymai cyst
N ependymal cyst of the spinal cord is rare. Reports of four such cases have appeared in the literature since 1938.a,4,7," We are describing a case with an extramedullary intradural ependymal cyst of the spinal cord, with a discussion of the clinical features and a nosologic classification of ependymal lined cysts.
A
Case Report
This 58-year-old woman was admitted to the hospital 6 months after the sudden onset of a sharp, shooting pain which radiated from the lumbosacral region into the left posterior thigh. The pain, which she had not experienced prior to this incident, was accompanied by numbness of the entire left leg. Subsequently the numbness disappeared but an aching pain of the left buttock persisted. In addition, the radicular pain would recur in association with coughing, straining, prolonged sitting and back flexion. At the time of admission, she denied focal weakness or sensory symptoms, but described urinary incontinence, frequent nocturia, and urinary J. Neurosurg. / Volume 43 / December, 1975
9 spinal cord
hesitancy. There was no prior history of significant back pain or injury. The past medical history included a hysterectomy for carcinoma in situ 20 years previously, cholecystectomy, thyroidectomy for diffuse glandular hypertrophy, and diabetes mellitus. Examination. General physical examination on admission showed an obese woman. Back examination revealed mild lumbar vertebral tenderness, but no muscle spasm or limitation of motion. Hamstring and buttock tenderness was present on the left side. Straight leg raising was possible to 80 ~ without pain. Gait and station were normal as well as muscle strength in both legs. The right patellar reflex was hypoactive. Both ankle reflexes were normal. Hypalgesia was present along the right and left lateral thigh. Anal sphincter contraction and cutaneous reflexes were diminished. An electromyogram demonstrated muscle denervation in the L5-S1 distribution bilaterally. Lumbosacral spine films did not demonstrate any abnormalities. A myelogram (Fig. 1) demonstrated a multilobu757
J. A. Mosso and M. A. Verity
FIG. 1. Myelogram demonstrating multilobulated intradural, extramedullary mass at the T12-L1 interspace. Plain films of the spine were normal.
lated, intradural lesion at the T12-L1 interspace on the left. An additional finding was a right L4-5 disc protrusion. Operation. A T I 2 - L 1 laminectomy was performed and the conus retracted medially. A cystic lesion was encountered intradurally, anterolateral to the spinal cord. The thin, transparent cyst wall contained a milky, opaque fluid. The cyst was entirely intradural and extra-axial. Although adherent to the arachnoid, the cyst wall was not contiguous with the arachnoid or dura and was easily dissected free of the meninges. Unfortunately, the cyst was ruptured during removal and the contents lost. Postoperatively, the patient's back and radicular pain were relieved, and on follow-up 6 months later she was asymptomatic. Pathological Study. The collapsed cyst was totally embedded in paraffin, routine sections prepared and stained with hematoxylin and eosm, periodic acid-Schiff, muci-carmine, modified G~Smori-trichrome, Holtzer, and phosphotungstic acid hematoxylin ( P T A H ) stains. Microscopic study revealed a single, convoluted, thin-walled structure (Fig. 2). T h e lining consisted of pseudostratified cuboidal epithelium, was focally hyperplastic, and alternately atrophic. Cilia were identified, especially over the hyperplastic zones (Fig. 3). A basement m e m b r a n e was ill defined. The underlying, nonglial stroma was delicate, generally acellular, focally
TABLE 1 Clinical attd pathological details of reported cases of ependymal cysts of the spinal cord
Author, Year Hyman, et al., 1938
Age, Sex Clinical Features 7 M
cervical pain, 5 mos
Moore & Book, 1966
17 M
neck injury
Hoffman, 1960 Wisoff & Ghatak, 1971
6M 44 M
Mosso & Verity, 1975
58 F
-low back & radicular pain to rt thigh; retinitis pigmentosa sudden onset It radicular pain; denervation L5-S 1
758
Location, Radiology
Pathology
anterior cervicodorsal; dilatation ependymal cyst of cervical canal; laminar fusion C-7 and T-1 ventral to cervical cord; ependymal cyst, dilatation of cervical canal; 2 cm; cilia not fusion bodies C3-5; seen; vacuolated spina bifida C-7 & T-1 cytoplasm; hemosiderin anterior spinal cord arachnoid cyst thoracolumbar; thinning of ependymal cyst, 3 cm pedicles L-1 and L-2; myelogram showed block at L-1 myelogram showed anterolateral lobulated intradural mass T12-L1; disc protrusion L4-5
ependymal cyst; ciliated, pseudostratified "ballooned" cytoplasm
J. Neurosurg. / Volume 43 / December, 1975
Ependymal cyst of the spinal cord hyalinized and without other structure. The epithelial cells appeared ballooned and vacuolated but failed to stain for mucin or other polysaccharide material. Discussion This ependymal cyst of the spinal cord is similar to that reported by Wisoff and Ghatak.t' The diagnosis of an extramedullary, intradural ependymal cyst was established by its position, by the simple nature of the cyst wall consisting of a ciliated, pseudostratified, cytologically benign epithelium, and by the absence of subependymal glial elements in the wall, mucoussecreting cells in the epithelium, and other stromal teratomatous elements. These features help to differentiate this lesion from cysts of teratomatous origin 6'~3 including the epidermoid and dermoid variants; cysts of enterogenous origin; ~,5,t~ and true ependymal cysts usually related to subependymal glial tissue occurring in the conus medullaris, s The closely related cyst reported by Rewcas-
Ftc. 2. Collapsed, thin-walled cyst lined by focally hyperplastic and atrophic pseudostratified epithelium. The wall is acellular and hyalinized. H & E , • 90. J. Neurosurg. / Volume 43 / December, 1975
tie and Francouer, ~ consisted of ciliated columnar cells lining a fibrous cyst wall with an admixture of mucin-containing cells and cells showing prominent intracellular bridges. Differentiating teratomatous cysts from those of enterogenous origin may be artificial, but the former are usually associated with glandular, fat, or other mesenchymal elements in the supporting stroma. In previously reported cases (Table 1), significant dilatation of the cervical canal with disturbance of associated bone laminae or pedicles has been a constant feature? ''a Our case did not reveal such bone abnormalities. The relationship to trauma is equivocal but established in the cases of Moore and Book, 7 and Wisoff and Ghatak? 4 Although the sudden onset of symptoms is not easily explained, the clinical presentation in this patient is consistent with that of a mass compressing the conus and caudal roots. Clinical relief following removal of the cyst supports this impression. The right L4-5 disc protrusion was probably incidental.
FIG. 3. Ciliated segment of pseudostratified epithelium. Some cytoplasmic vacuolization is also seen. H & E, • 400. 759
J. A. M o s s o a n d M. A. V e r i t y TABLE 2 Nosologic classification of ependymal lined cysts
Classification
Author, Year
simple intramedullary Nasser, et al., 1968 extramedullary Hoffman, 1960 Wisoff & Chatak, 1971 Mosso & Verity, 1975 Hyman, et aL, 1938 mixed Moore & Book, 1966 Sloof, et al., 1964 teratomatous Rewcastle & Francoeur, 1964 Kubie & Fulton, 1928 enterogenous intramedullary Knight, et aL, 1955 Rhaney & Barclay, 1959 Scoville, et al., 1963 extramedullary Harriman, 1958 Hoefnagel, et al., 1962 neuroepithelial Rubinstein, 1972 (colloid cyst)
The differential diagnosis of intradural cysts of the spinal cord includes syringomyelia and teratomatous, arachnoid, enterogenous, and parasitic cysts. Sometimes the exact nosologic classification of ependymal lined cysts in the central nervous system is open to argument. We present a classification (Table 2) of ependymal lined cysts based on previous case reports and our own study. We agree with the postulate of Hyman, e t a l . , 4 and Wisoff and Ghatak 14 that ependymal cysts could result from isolation of ependymal cells from either the roof or floorplates with secondary cyst formation. The preference of these cysts for the anterior aspect seen in prior case reports and in our own is interesting.
References 1. Harriman DGF: An intraspinal, enterogenous cyst. J Pathoi Bact 75:413-419, 1958 2. Hoefnagel D, Benirschke K, Duarte J: Teratomatous cysts within the vertebral canal. Observations on the occurrence of sex chromatin. J Neurol Neurosurg Psychiatry 25:159-164, 1962
760
3. Hoffman GT: Cervical arachnoidal cyst. Report of a six-year-old Negro male with a recovery from quadraplegia. J Neurosurg 17:327-330, 1960 4. Hyman I, Hamby WB, Sanes S: Ependymal cyst of the cervicodorsal region of the spinal cord. Arch Neuroi Psychiatry 40:1005-1012, 1938 5. Knight G, Griffiths T, Williams I: Gastrocytoma of the spinal cord. Br J Surg 42:635-638, 1955 6. Kubie LS, Fulton JF: A clinical and pathological study of two teratomatous cysts of the spinal cord containing mucous and ciliated cells. Surg Gynec Obstet 47:297-311, 1928 7. Moore MT, Book MH: Congenital cervical ependymal cyst. Report of a case with symptoms precipitated by injury. J Neurosurg 24:558-561, 1966 8. Nassar SI, Correll JW, Houspian EM: IntrameduUary cystic lesions of the conus medullaris. J Neuroi Neurosurg Psychiatry 31:106-109, 1968 9. Rewcastle NB, Francouer J: Teratomatous cysts of the spinal canal with "sex chromatin" studies. Arch Neurol 11:91-99, 1964 10. Rhaney K, Barclay GPT: Enterogenous cysts and congenital diverticula of the alimentary canal with abnormalities of the vertebral column and spinal cord. J Pathol Bact 77:457-571, 1959 11. Rubinstein L J: Tumors of the central nervous system, in Atlas of Tumor Pathology, Fasc 6, 2nd series, 1972, p 287 12. Scoville WB, Manlapz JS, Otis RD, et al: Intraspinal enterogenous cyst. J Neurosurg 20:704-706, 1963 13. Sloof JL, Kernohan JW, MacCarty CS: Primary Intramedullary Tumors of the Spinal Cord and Filum Terminale. Philadelphia/London, WB Saunders, 1964 14. Wisoff HS, Ghatak NR: Ependymal cyst of the spinal cord: case report. J Neurol Neurosurg Psychiatry 34:546-550, 1971
Present address for Dr. Mosso: Division of Neurosurgery, University of Cincinnati, Cincinnati, Ohio. Address reprint requests to: M. Anthony Verity, M.D., Department of Pathology (Neuropathology), The Center for the Health Sciences, University of California at Los Angeles, Los Angeles, California 90024.
J. Neurosurg. / Volume 43 / December, 1975
JAMES A. MOSSO, M.D., AND M. ANTHONY VERITY, M.D. Divisions of Neurosurgery and Neuropathology, The Center for the Health Sciences, University of California at Los Angeles, Los Angeles, California
A case with extramedullary ependymal cyst of the spinal cord is presented. The clinical, operative, and pathological findings are discussed and a review of previous cases and a nosologic classification of ependymal lined cysts given. KEY WORDS
9
ependymai cyst
N ependymal cyst of the spinal cord is rare. Reports of four such cases have appeared in the literature since 1938.a,4,7," We are describing a case with an extramedullary intradural ependymal cyst of the spinal cord, with a discussion of the clinical features and a nosologic classification of ependymal lined cysts.
A
Case Report
This 58-year-old woman was admitted to the hospital 6 months after the sudden onset of a sharp, shooting pain which radiated from the lumbosacral region into the left posterior thigh. The pain, which she had not experienced prior to this incident, was accompanied by numbness of the entire left leg. Subsequently the numbness disappeared but an aching pain of the left buttock persisted. In addition, the radicular pain would recur in association with coughing, straining, prolonged sitting and back flexion. At the time of admission, she denied focal weakness or sensory symptoms, but described urinary incontinence, frequent nocturia, and urinary J. Neurosurg. / Volume 43 / December, 1975
9 spinal cord
hesitancy. There was no prior history of significant back pain or injury. The past medical history included a hysterectomy for carcinoma in situ 20 years previously, cholecystectomy, thyroidectomy for diffuse glandular hypertrophy, and diabetes mellitus. Examination. General physical examination on admission showed an obese woman. Back examination revealed mild lumbar vertebral tenderness, but no muscle spasm or limitation of motion. Hamstring and buttock tenderness was present on the left side. Straight leg raising was possible to 80 ~ without pain. Gait and station were normal as well as muscle strength in both legs. The right patellar reflex was hypoactive. Both ankle reflexes were normal. Hypalgesia was present along the right and left lateral thigh. Anal sphincter contraction and cutaneous reflexes were diminished. An electromyogram demonstrated muscle denervation in the L5-S1 distribution bilaterally. Lumbosacral spine films did not demonstrate any abnormalities. A myelogram (Fig. 1) demonstrated a multilobu757
J. A. Mosso and M. A. Verity
FIG. 1. Myelogram demonstrating multilobulated intradural, extramedullary mass at the T12-L1 interspace. Plain films of the spine were normal.
lated, intradural lesion at the T12-L1 interspace on the left. An additional finding was a right L4-5 disc protrusion. Operation. A T I 2 - L 1 laminectomy was performed and the conus retracted medially. A cystic lesion was encountered intradurally, anterolateral to the spinal cord. The thin, transparent cyst wall contained a milky, opaque fluid. The cyst was entirely intradural and extra-axial. Although adherent to the arachnoid, the cyst wall was not contiguous with the arachnoid or dura and was easily dissected free of the meninges. Unfortunately, the cyst was ruptured during removal and the contents lost. Postoperatively, the patient's back and radicular pain were relieved, and on follow-up 6 months later she was asymptomatic. Pathological Study. The collapsed cyst was totally embedded in paraffin, routine sections prepared and stained with hematoxylin and eosm, periodic acid-Schiff, muci-carmine, modified G~Smori-trichrome, Holtzer, and phosphotungstic acid hematoxylin ( P T A H ) stains. Microscopic study revealed a single, convoluted, thin-walled structure (Fig. 2). T h e lining consisted of pseudostratified cuboidal epithelium, was focally hyperplastic, and alternately atrophic. Cilia were identified, especially over the hyperplastic zones (Fig. 3). A basement m e m b r a n e was ill defined. The underlying, nonglial stroma was delicate, generally acellular, focally
TABLE 1 Clinical attd pathological details of reported cases of ependymal cysts of the spinal cord
Author, Year Hyman, et al., 1938
Age, Sex Clinical Features 7 M
cervical pain, 5 mos
Moore & Book, 1966
17 M
neck injury
Hoffman, 1960 Wisoff & Ghatak, 1971
6M 44 M
Mosso & Verity, 1975
58 F
-low back & radicular pain to rt thigh; retinitis pigmentosa sudden onset It radicular pain; denervation L5-S 1
758
Location, Radiology
Pathology
anterior cervicodorsal; dilatation ependymal cyst of cervical canal; laminar fusion C-7 and T-1 ventral to cervical cord; ependymal cyst, dilatation of cervical canal; 2 cm; cilia not fusion bodies C3-5; seen; vacuolated spina bifida C-7 & T-1 cytoplasm; hemosiderin anterior spinal cord arachnoid cyst thoracolumbar; thinning of ependymal cyst, 3 cm pedicles L-1 and L-2; myelogram showed block at L-1 myelogram showed anterolateral lobulated intradural mass T12-L1; disc protrusion L4-5
ependymal cyst; ciliated, pseudostratified "ballooned" cytoplasm
J. Neurosurg. / Volume 43 / December, 1975
Ependymal cyst of the spinal cord hyalinized and without other structure. The epithelial cells appeared ballooned and vacuolated but failed to stain for mucin or other polysaccharide material. Discussion This ependymal cyst of the spinal cord is similar to that reported by Wisoff and Ghatak.t' The diagnosis of an extramedullary, intradural ependymal cyst was established by its position, by the simple nature of the cyst wall consisting of a ciliated, pseudostratified, cytologically benign epithelium, and by the absence of subependymal glial elements in the wall, mucoussecreting cells in the epithelium, and other stromal teratomatous elements. These features help to differentiate this lesion from cysts of teratomatous origin 6'~3 including the epidermoid and dermoid variants; cysts of enterogenous origin; ~,5,t~ and true ependymal cysts usually related to subependymal glial tissue occurring in the conus medullaris, s The closely related cyst reported by Rewcas-
Ftc. 2. Collapsed, thin-walled cyst lined by focally hyperplastic and atrophic pseudostratified epithelium. The wall is acellular and hyalinized. H & E , • 90. J. Neurosurg. / Volume 43 / December, 1975
tie and Francouer, ~ consisted of ciliated columnar cells lining a fibrous cyst wall with an admixture of mucin-containing cells and cells showing prominent intracellular bridges. Differentiating teratomatous cysts from those of enterogenous origin may be artificial, but the former are usually associated with glandular, fat, or other mesenchymal elements in the supporting stroma. In previously reported cases (Table 1), significant dilatation of the cervical canal with disturbance of associated bone laminae or pedicles has been a constant feature? ''a Our case did not reveal such bone abnormalities. The relationship to trauma is equivocal but established in the cases of Moore and Book, 7 and Wisoff and Ghatak? 4 Although the sudden onset of symptoms is not easily explained, the clinical presentation in this patient is consistent with that of a mass compressing the conus and caudal roots. Clinical relief following removal of the cyst supports this impression. The right L4-5 disc protrusion was probably incidental.
FIG. 3. Ciliated segment of pseudostratified epithelium. Some cytoplasmic vacuolization is also seen. H & E, • 400. 759
J. A. M o s s o a n d M. A. V e r i t y TABLE 2 Nosologic classification of ependymal lined cysts
Classification
Author, Year
simple intramedullary Nasser, et al., 1968 extramedullary Hoffman, 1960 Wisoff & Chatak, 1971 Mosso & Verity, 1975 Hyman, et aL, 1938 mixed Moore & Book, 1966 Sloof, et al., 1964 teratomatous Rewcastle & Francoeur, 1964 Kubie & Fulton, 1928 enterogenous intramedullary Knight, et aL, 1955 Rhaney & Barclay, 1959 Scoville, et al., 1963 extramedullary Harriman, 1958 Hoefnagel, et al., 1962 neuroepithelial Rubinstein, 1972 (colloid cyst)
The differential diagnosis of intradural cysts of the spinal cord includes syringomyelia and teratomatous, arachnoid, enterogenous, and parasitic cysts. Sometimes the exact nosologic classification of ependymal lined cysts in the central nervous system is open to argument. We present a classification (Table 2) of ependymal lined cysts based on previous case reports and our own study. We agree with the postulate of Hyman, e t a l . , 4 and Wisoff and Ghatak 14 that ependymal cysts could result from isolation of ependymal cells from either the roof or floorplates with secondary cyst formation. The preference of these cysts for the anterior aspect seen in prior case reports and in our own is interesting.
References 1. Harriman DGF: An intraspinal, enterogenous cyst. J Pathoi Bact 75:413-419, 1958 2. Hoefnagel D, Benirschke K, Duarte J: Teratomatous cysts within the vertebral canal. Observations on the occurrence of sex chromatin. J Neurol Neurosurg Psychiatry 25:159-164, 1962
760
3. Hoffman GT: Cervical arachnoidal cyst. Report of a six-year-old Negro male with a recovery from quadraplegia. J Neurosurg 17:327-330, 1960 4. Hyman I, Hamby WB, Sanes S: Ependymal cyst of the cervicodorsal region of the spinal cord. Arch Neuroi Psychiatry 40:1005-1012, 1938 5. Knight G, Griffiths T, Williams I: Gastrocytoma of the spinal cord. Br J Surg 42:635-638, 1955 6. Kubie LS, Fulton JF: A clinical and pathological study of two teratomatous cysts of the spinal cord containing mucous and ciliated cells. Surg Gynec Obstet 47:297-311, 1928 7. Moore MT, Book MH: Congenital cervical ependymal cyst. Report of a case with symptoms precipitated by injury. J Neurosurg 24:558-561, 1966 8. Nassar SI, Correll JW, Houspian EM: IntrameduUary cystic lesions of the conus medullaris. J Neuroi Neurosurg Psychiatry 31:106-109, 1968 9. Rewcastle NB, Francouer J: Teratomatous cysts of the spinal canal with "sex chromatin" studies. Arch Neurol 11:91-99, 1964 10. Rhaney K, Barclay GPT: Enterogenous cysts and congenital diverticula of the alimentary canal with abnormalities of the vertebral column and spinal cord. J Pathol Bact 77:457-571, 1959 11. Rubinstein L J: Tumors of the central nervous system, in Atlas of Tumor Pathology, Fasc 6, 2nd series, 1972, p 287 12. Scoville WB, Manlapz JS, Otis RD, et al: Intraspinal enterogenous cyst. J Neurosurg 20:704-706, 1963 13. Sloof JL, Kernohan JW, MacCarty CS: Primary Intramedullary Tumors of the Spinal Cord and Filum Terminale. Philadelphia/London, WB Saunders, 1964 14. Wisoff HS, Ghatak NR: Ependymal cyst of the spinal cord: case report. J Neurol Neurosurg Psychiatry 34:546-550, 1971
Present address for Dr. Mosso: Division of Neurosurgery, University of Cincinnati, Cincinnati, Ohio. Address reprint requests to: M. Anthony Verity, M.D., Department of Pathology (Neuropathology), The Center for the Health Sciences, University of California at Los Angeles, Los Angeles, California 90024.
J. Neurosurg. / Volume 43 / December, 1975
