J Neurosurg 74:816-820, 1991

Solitary dorsal intramedullary schwannoma Case report PNI'RICK HERREGODTS, M.D., Mlcnt.:L VLOEBERGIIS, M.D., Emc SCIIMEDDING, M.D., ANITA GOOSSENS, M.D., TADEUSZ STADNIK, M.D., AND JEAN D'HAENS, M.D.

DepartmenCs ~?/ Neurosurgery, Neurology, PaHwlogy, and Radioh)gy, Vrije Universiteit Brussel, Brussel.~, Belgitm7 A case of solitary dorsal intramedullary schwannoma diagnosed by magnetic resonance imaging and treated surgically is reported. The authors review the previously published cases. The possible etiology of the tumor as well as some difficulties encountered in the diagnostic procedure and treatment are discussed. KEY WORDS

'

intramedullary lesion

schwannoma

neurinoma

spinal cord tumor

LXHOUGH it has been reported that schwannomas (also called neurinomas or neurilemomas) comprise approximately' 30% of primary intraspinal neoplasms, ~3'37 intramedullary neurilemomas are rare. According to recent review papers, only 25 cases have been reported in patients who had no evidence of yon Recklinghausen's disease. ~.~-~42~'In addition, 11 cases of intraparenchymal schwannomas of the brain and brain stem have been reported. 2 Because the presumed cell of origin of the schwannoma is the Schwann cell, l~ which is not normally found within the parenchyma of the brain and spinal cord, it is not surprising that these lesions are rare. Several theories have been advanced to explain the presence of these tumors within the central nervous system (CNS). None has gained universal acceptance. We report an additional case of intramedullary schwannoma of the dorsal spinal cord and review the literature on these rare neoplasms. With the increasing use of magnetic resonance (MR) imaging as the initial diagnostic procedure and the preference for operative management of intramedullary tumors of all types, these lesions are expected to be encountered more frequently in the literature over the next years.

A

Case Report This 49-year-old woman complained of upper thoracic midline back pain over a period of 5 years. Over the 2 years prior to admission she also experienced the 816

insidious onset of vague dysesthetic pains in the left shoulder, scapular region, and left breast. In addition, she noted a loss of strength in the left lower extremity with increasing walking problems. There was no family histo~ of yon Recklinghausen's disease, and the physical examination revealed no stigmata. Examination. There was mild pain of the upper dorsal spine without radiation. Motor examination showed increased tone in the left extremity. Deeptendon reflexes were hyperactive in the left leg with presence of a knee and ankle clonus. The left plantar reflex revealed a Babinski sign. Gait was broad-based due to spasticity at the left side. Sensitivity was normal in the upper extremities, the chest region, and the abdomen. Pinprick perception, discrimination, as well as proprioception were disturbed in the left lower extremity. Anal reflex was present on the right and absent on the left. Plain x-ray films of the dorsal spine, left shoulder, left scapula, and thorax were normal. Sagittal T~weighted pre-contrast MR images demonstrated an enlarged spinal cord between T-1 and T-5 (Fig. 1 left). After gadolinium injection, a high-density well-delineated lesion was discovered at the T-3 level (Fig. 1 right). Axial postgadolinium T~-weighted MR images also demonstrated a large tumoral mass occupying up to 90% of the spinal canal volume (Fig. 2). On MR examination it was impossible to identify whether it was an intradural extramedullary or an intramedullary tumor.

J. Neurosurg. / Volume 74/May, 1991

Solitary dorsal intramedullary schwannoma

Fl(;. 1. Sagittal T~-weighled spin-echo magnetic resonance images. Leli: Image without gadolinium enhancement showing enlargement of the spinal cord extending from T-1 to T-5 and a central hypointensity area at the T-3 level. Ri,q,/ll:Image after infusion of gadolinium showing homogeneous and intense contrast uptake by the sharply delineated tumor mass al the T-3 level.

Operation A laminectomy was performed from T2 to T-5. When the dura mater was opened, the spinal cord was found to be expanded in this region, with a small longitudinal area of grayish-green discoloration on its left paramedian dorsal side. Close examination of the dorsal roots of T-2 to T-4 on both sides revealed no abnormality. Longitudinal incision of the pia mater at the site of the discoloration disclosed a well-encapsulated, firm, slightly lobulated intramedullary tumor. Its grayish-green capsule was densely adherent to the cord substance, but the spinal cord itself did not appear to be infiltrated by the tumor. There was no connection with a nerve root. The tumor was completely removed microsurgically using bipolar coagulation and ultrasonic aspiration.*

Discussion Clinical Factory Intramedullary schwannomas are rare because the fibers in the CNS do not contain a myelin sheath or Schwann cells. In a review article, Ross, et al., 26 reported that intramedullary neurinomas constituted 0.3% of intraspinal neoplasms. We found 35 cases in the literature in addition to our own (Table 1). Eleven

Postoperative Course. In the immediate postoperative period, there was a slight increase in spastic paresis of the left leg. Disturbance of sensitivity remained unchanged. At follow-up review 6 weeks later, the paraparesis had recovered well, reaching a better functional status than prior to the operation. PathologicalFindings. Histological examination revealed a connective-tissue tumor composed predominantly of compact spindle-shaped cells, arranged in short bundles or interlacing fascicles (Fig. 3). This pattern was consistent with the Antoni A area of a typical schwannoma. There were no signs of malignancy. Immunocytochemical staining for glial fibrillary acidic protein was negative and staining for neuron-specific enolase and S-100 protein was positive.

* Ultrasonic surgical aspirator manufactured by Cavitron Surgical Systems, Inc., Stamford, Connecticut.

J. Neurosurg. / Volume 74 / May. 1991

Fi6. 2. Axial postgadolinium T,-weighted spin-echo magnetic resonance image showing a large hyperintense tumor mass almost fully occupying the spinal canal. The relationship with the spinal cord tissue is unclear.

817

P. Herregodts, et al. patients (31%) were reported over the last decade since more cases of intramedullary tumors have been diagnosed by noninvasive techniques such as MR imaging and more spinal tumors were subjected to operative treatment. Considering all cases reported thus far, it is evident that males are affected more commonly than females in a ratio of 2:l (24 cases in males and 12 cases in females, Table I). The median age of the 36 patients was 40 years. The cervical cord was affected in 22 cases (63%), the thoracic cord in nine (26%), and the lumbosacral cord in four (11%). The time lag between the appearance of the first symptoms and treatment ranged from 6 weeks ~: to 12 years) ~ with a mean interval of 2.8 + 2.7 years (_+ standard deviation). According to Lesoin, el al., ~4the major clinical signs are motor deficiency (50% of patients), diminished sensitivity (30%), and loss of genitourinary or anorectal control {16%). The patients seemed to be little concerned by the motor deficiency; it was pain or paresthesia, lasting for several months or years, that finally motivated them to consult a physician. When the syndrome is fully developed, there are no pathognomonic clinical signs that allow differentiation between an intramedullary and extramedullary tumor. Although solitary intramedullary schwannomas are usually located in the posterior or posterolateral part of the spinal cord, alteration of deep sensitivity is less frequently encountered than motor weakness and pain. The pain and dysesthesia described by the patients are difficult to study objectively since hypesthesia with rather vague boundaries is more frequently encountered than anesthesia or typically radicular pain. Modification of sensitivity and pain was reported in 70% of the reported cases. A slowly developing unilateral or predominantly unilateral motor deficit, sometimes accompanied by amyotrophy with alternating periods of impairment and remission, is frequently mentioned in the clinical history. ~-14

Investigative Findings Plain x-ray studies may contribute in the investigation but are of no help in differentiating an intramedullary from an intradural extramedullary lesion. The usual signs are widening of the space between the pericles, narrowing of the pedicles themselves, and increase in the anteroposterior measurements of the spinal canal. Some cases of associated scoliosis have been reported. We believe that MR imaging has taken the place of myelography in localizing and delineating an intraspinal tumor. This technique is also safer for the patient, avoiding possible exacerbation of the neurological condition by lumbar puncture below the tumor during myelography. The use of gadolinium-enhanced MR imaging greatly contributes to delineating the extent of the tumor, indicating possible invasion of the spinal cord itself, and differentiating it from cord edema, s3 Once again, differentiation between intramedullary and intradural extramedullary tumors remains difficult. 81 8

FJr 3. Pholomicrograph showing a connective-tissue lumot composed of spindle-shaped cells, arranged in short bundles or interlacing fascicles consistent with an Antoni A area of a typical schwannoma. H & E, x 60.

S#e q/" Origin: Palhogenesis The absence of Schwann cells within the brain and spinal cord in normal individuals has raised speculation as to the patbogenesis of these tumors. Hypotheses include: 1) central displacement of Schwann cells during embryonic development; 22'35 2) Schwann ceils ensheathing aberrant intramedullary nerve fibers; ~'m'~2 3) Schwann cells extending along the intramedullary perivascular nerve plexus; 2~243~ 4) possible neoplastic growth from dorsal root Schwann cells located in a "critical area," as suggested by Mason and Keigher, ~v where posterior roots lose their sheaths on entering the pia mater; >37 and 5) transformation of pial cells of neuroectodermal origin into Schwann cells, x Without putting forward one of the formal hypotheses, Wood, et al.,37 made two important observations: first that schwannomas are all posteriorly or posterolaterally located, and second that the tumoral vascular plexus, if seen during surgery, always originates from anterior spinal arteries and never from posterior spinal arteries. A case of dumbbell-shaped neurilemoma with intramedullary and extramedullary components was reported by Gorman, el al.,~ supporting the hypothesis of a "critical area." In our case, the tumor was located posterolaterally and the vascular pedicle originated from a branch of the anterior spinal artery. The tumor was also located in an intramedullary subpial position. This raises the possibility that the intramedullary nerve plexus might be the source of origin of the tumor in our patient. Since schwannomas occur in the brain, the brain stem, -~ and the spinal cord, a single etiological theory is likely. In this case, the hypothesis of an ectopic origin of all CNS schwannomas is certainly the most attractive one. Therapy The fact that schwannomas are usually benign, well delineated, and posteriorly located makes them eminently suited for surgical excision. We believe that complete resection is the treatment of choice. Since Y. Neurosurg. / Volume 74/May, 199i

Solitary dorsal i n t r a m e d u l l a r y s c h w a n n o m a TABLE 1 Clinical s u m m a r y 0 f 36 cases q/intramedldlar T sehwam~oma o f the spinal cord without yon Recklinghausen's neurqfibroma*

Authors & Year Penfield, 1932 Rasmussen, et al., 1940 Roka, 1951 Riggs & Clary, 1957 Ramamurthi, eta/.. 1958 Lang & Bridge, 1959 Scott & Bentz, 1962 La, el al., 1963 McCormick, 1964 Sloofl', et al., 1964 Guidetti, 1967 Mason & Keigher, 1968 Chigasaki & Pennybacker, 1968 Van Duinen, 1971 Bharati & Ramamurthi, 1 9 7 2 Fabres, et al., 1972 Cambier, el al., 1974 Wood, et al., 1975 Schmitt. 1975 lsu. et cd., 1976 Pardatscher, et al., 1979 Vailati, e* al., 1979 Shalit& Sandbank, 1981 Cantore, et al., 1982 Lesoin, cl al.. 1983 Rout, el al., 1983 Sharma, el al., 1984 Ross, el al.. 1986 Gorman, el al., 1989 Herregodts, et al., 1991

Sex

Location

M M M M M M M F M M M M -M F M . M M M M F M F F M F F M F F M M F F F

C-5 C4-7 cervical C-4,C-5 T-2 cervical thoracic T-3,T-4 C-4,C-5 C2-5 L-2 C4-7 conus T8-10 T-3 C-3 . T-2,T-3 C2-4 C1-3 conus C-I C4-T9 T-8,T-9 C2-T2 T 12-L 1 C3-5 C3-7 conus C2-6 C2-5 C2-6 C-4,C-5 C2-TI C2-5 T-3,T-4

Duration of Symptoms 8 yrs 4 yrs 3 yrs 3 yrs 9 mos 1 yr 3 yrs 12 yrs 3 mos 18 mos 6 wks 4 yrs -3 mos --. 13 mos 16 mos 3 mos 6 mos 6 mos 9 mos 12 mos 6 mos 2 yrs 6 mos 5 yrs 5 yrs 5 yrs 18 mos 4 mos 4 yrs 8 mos 5 yrs

Therapy,

Outcome

subtotal resection subtotal resection subtotal resection autopsy finding total resection x2 total resection total resection subtotalresection radiationtherapy, total resection subtotalresection autopsyfinding -total resection total resection subtotal resection total resection . . subtotalresection total resection radiationtherapy autopsyfinding subtotalresection decompressivelaminectomy total resection radiation therapy, total resection total resection total resection total resection total resection subtotal,then total resection subtotalresection subtotal,then total resection total resection subtotal resection subtotal,then total resection total resection

-partial recovery worse partial recovery partial recover?' worse stable deficit partialrecovery partial recovery --recovery partial recovery -partial recovery worse died (pulm embol) --died (progressionof disease) partial recovery recovery recovery partial recovery recovery recovery recovery partial recovery recovery recovery partial recovery partial recover)' partial recover)'

* Pulm embol = pulmonary embolism: - - = data not available or not applicable.

schwannomas are sometimes difficult to differentiate from gliomas of the spinal cord on MR imaging or during surgical exploration, every effort should be m a d e to obtain a biopsy s p e c i m e n from all i n t r a m e d u l l a r y t u m o r s so as to reach a correct diagnosis on frozen sections. Failure to obtain a tissue diagnosis for intramedullary spinal cord lesions has led to avoidable progression o f disease and to the necessity o f a s e c o n d

intervention, 1(,,27.31.37 Of the 36 reported cases, surgery produced complete neurological recovery in 30% o f the patients a n d partial recovery or a stable functional deficit in 52%. T h e best results were o b t a i n e d in those patients in w h o m c o m plete resection o f the t u m o r could be p e r f o r m e d . In the r e m a i n i n g 18% o f cases, the neurological c o n d i t i o n deteriorated or the patient died o f c o m p l i c a t i o n s after surgical t r e a t m e n t . Neurosurgical t e c h n i q u e s c o m b i n ing the use o f a surgical m i c r o s c o p e a n d a Cavitron ultrasonic aspirator facilitated removal o f i n t r a m e d u l lary t u m o r s by reducing t u m o r volume, allowing m i n imal retraction o f the spinal cord itself. J, N e u r o s u r g . / V o h t r n e 7 4 / M a y ,

1991

Conclusions S c h w a n n o m a s o f the spinal cord, although rare tumors, are today m o r e frequently e n c o u n t e r e d due to better investigative techniques. In particular, M R investigation m a k e s the diagnostic process safer for the patient and enables g o o d evaluation o f the delineation a n d extent o f spinal t u m o r s . Since s c h w a n n o m a s are always benign, surgical exploration of all intraspinal t u m o r s with histological c o n f i r m a t i o n should be considered.

References 1. Ade[man LS, Aronson SM: Intramedullary nerve fiber and Schwann cell proliferation within the spinal cord (schwannosis). Neurology 22:726-73 l, 1972 2. Aryanpur J, Long DM: Schwannoma of the medulla oblongata. Case report. J Neurosurg 69:446-449, 1988 3. Bharati RS, Ramamurthi B: Intramedullary schwannoma. Proc Inst Neurol Madras 2:91, 1972 4. Cambier J, Masson M, Hurth M, et al: Syndrome cor810

P. Herregodts, et al.

5. 6. 7. 8. 9. 10. 11. I2. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.

820

donal post6rieur unilatdral par neurinome intra-m6dullaire. Syncin6sies homolatdrales d'imitation. Rev Neurol 130:18%199, 1974 Cantore G, Ciappetta P, Delfini R. ct al: Intramedullary spinal neurinomas. Report of two cases. J Neurosurg 57: 143-147, 1982 Chigasaki H, Pennybacker JB: A long follow-up study of 128 cases of intramedullary spinal cord tumors. Neurol Med Chir 10:25-66, 1968 Fabres A, Conocente Y, Chiorino S: Neurinoma intramedullar dorsal. Presentacion de un caso. Clin Neurocir 30:100-102, 1972 Gorman PH, Rigamonti D, Joslyn JN: Intramedullary and extramedullary schwannoma of the cervical spinal cord - - case report. Surg Neurol 32:459-462, 1989 Guidetti B: Intramedullary tumors of the spinal cord. Aeta Neurochir 17:7-23, 1967 Hughes JT, Brownell B: Aberrant nerve fibres within the spinal cord. a Nenrol Neurosurg Psychiatry 26:528-534, 1963 Isu T, Kunio T, Mitsumori K, et al: Cited in Reference 26 Koeppen AH, Ordinario AT, Barton KD: Aberrant intramedullary peripheral nerve fibers. Acts Neurol 18: 567-573, 1968 Lang EF Jr, Bridge C: lntramedullaryspinal cord tumors. Snrg Clin North Am 39:831-839, 1959 Lesoin F, Delandsheer E, Krivosic I, et al: Solitary intramedullary schwannomas. Surg Neurol 19:51-56, 1983 Lodding P, Kindblom LG, Angervall L, et at: Cellular schwannoma. A clinicopathologic study of 29 cases. Virchows Arch Pathol Anat 416:237-248, 1990 Lu AT, Kypfidakis G, Abbott KH, et al: Intramedullary neurofibromas of the cervical cord. Report of two cases. Bull Los Angeles Neurol Sue 28:31-36, 1963 Mason TH, Keigher HA: Intramedullary spinal neurilemomas. Case report, d Neurosurg 29:414-416, 1968 McCormick WF: IntrameduUary spinal cord schwannoma. A unique case. Arch Pathol 77:378-382, 1964 Pardatscher K, Iraci G, Cappellotto P, et al: Multiple intramedullary neurinomas of the spinal cord. Case report. J Neurosorg 50:817-822, 1979 Penfield W: Cytology and Cellular Pathology of the Nervous System. New York: Paul B Hoeber, 1932, Vol 3, p 1013 Prakash B, Roy S, Tandon PN: Sehwannoma of the brain stem. Case report. J Neurosurg 53:121-123, 1980 Ramamurthi B, Anguli VC, Iyer CGS: A case of intramedullary neurinoma. J Neurol Neurosurg Psychiatry 21:92-94, 1958

23. Rasmussen TB, Kernohan JW, Adson AW: Pathologic classification, with surgical consideration of intraspinal tumors. Ann Surg 3:513-530, 1940 24. Riggs HE, Clan WU: A case of intramedullary sheath cell tumor of the spinal cord. Consideration of vascular nerves as a source of origin. J Neuropathol Exp Neurol 16:332-336, 1957 25. Roka L: Uber Klinik und Anatomie der Tumoren der Medulla oblongata-Halsmarkgrenze. Arch Psychiatr Nervenkr 186:413-436, 1951 26. Ross DA, Edwards MSB, Wilson CB: Intramedullary neurilemomas of the spinal cord: report of two cases and review of the literature. Neurosurgery 19:458-464, 1986 27. Rout D, Pillai SM, Radhakrishnan VV: Cervical intramedullary schwannoma. Case report. J Neurosurg 58: 962-964, 1983 28. Russell DS, Rubinstein L.I: Pathology of Tamours of the Nervous System, ed 3. London: Edward Arnold, 1971, pp 36-37 29. Schmitt HP: "Epi-" and intramedullary neurilemmoma of the spinal cord with denervation atrophy in the related skeletal muscles. J Neurol Germ 209:271-278, 1975 30. Scott M, Bentz R: Intramedullary neurilemmoma (neurinoma) of the thoracic cord. A case report. J Neuropathol Exp Neurol 21:194-200, 1962 31. Shalit MN, Sandbank U: Cervical intramedullary schwannoma. Surg Neurol 16:61-64, 1981 32. Sharma R, Tandon SC, Mohanty S, et al: Intramedullary neurofibroma of the cervical spinal cord: case report with review of the literature. Neurosurgery 15:546-548, 1984 33. Slasky BS, Bydder GM, Niendorf HP, et al: MR imaging with gadolinium-DTPA in the differentiation of tumor, syrinx, and cyst of the spinal cord. J Comput Assist Tomogr 11:845-850, 1987 34. Slooff JL, Kernohan JW, MacCarty CS: Primary Intramedullary Tumours of the Spinal Cord and Filum Terminale. Philadelphia: WB Saunders, 1964, pp 132-138 35. Vailati G, Occhiogrosso M, Troccoli V: Intramedullary thoracic schwannoma. Surg Neurol 11:60-62, 1979 36. Van Duinen DM: Het intramedullair neurinoom. Ned Tijdschr Geneeskd 115:1070-1074, 1971 37. Wood WG, Rothman LM, Nussbaum BE: Intramedullary neurilemoma of the cervical spinal cord. Case report. J Neurosurg 42:465-468, 1975 Manuscript received August 7, 1990. Address reprint requests to: Patrick Herregodts, M.D., Department of Neurosurgery, AZ-VUB, Laarbeeklaan 101, 1090 Brussels, Belgium.

J. Neurosurg. / Volume 74/May, 1991

Solitary dorsal intramedullary schwannoma. Case report.

A case of solitary dorsal intramedullary schwannoma diagnosed by magnetic resonance imaging and treated surgically is reported. The authors review the...
1MB Sizes 0 Downloads 0 Views