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Show f. Clill. NCllro-0l'hf11t1111111/. 5: )Y4-1YH, 14H5 © 1985 Raven Press, New York Compressive Optic Neuropathy and Ependymoma of the Third Ventricle JAMES D. RUTKA, M.D. JAMES A. SHARPE, M.D. LOTHAR RESCH, M. D. J. F. ROSS FLEMING, M.D. Abstract Progressive monocular visual loss was the presenting manifestation of a cystic ependymoma arising from the third ventricle. Extracerebral extension of the tumor into the prechiasmatic cistern compressed the right optic nerve. Subfrontal extension caused erosion of the planum sphenoidale. Subtotal excision of the tumor was foIlowed by cranial irradiation, and no further visual loss occurred. Extracerebral growth of primary intracerebral gliomas may cause optic neuropathy that is indistinguishable from other compressive neuropathies. Jefferson l emphasized that gliomas arising within the cerebrum may compress or invade the optic nerves. The glioma may be an astrocytoma, astroblastoma, or oligodendroglioma that originates from the frontal lobe, the temporal lobe, or the walls of the third ventricle. Ependymomas were not among the gliomas described. 1 We report the case of a patient with an ependymoma arising from the anterior aspect of the third ventricle; most of the tumor bulk extended outside the ventricle into the subfrontal region and involved the optic nerve, causing monocular visual loss. Case Report A 37-year-old woman complained of progressive visual loss in the right eye for 1 month. She had had intermittent headaches, occasionally associated with vomiting, during the previous From the Neuro-ophthalmology Unit, Divisions of Neurosurgery, Neurology and Neuropathology, and Playfair Neuroscience Unit, Toronto Western Hospital. University of To-ronto, Toronto, Ontario, Canada. . Write for reprint, to: J. A. Sharpe, M.D., Neuro-ophthalmology Unit, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario M5T 258, Canada. 194 year. Because her vision wor~ened, she was examined by an ophthalmologIst and referred to the Toronto Western Hospital for investigation. The patient had no symptoms of endocrine dysfunction and her past health had been good. At the time of admission to the hospital, her visual acuity was 20/200 in the right eye and 201 20 in the left eye. The right optic disc showed diffuse pallor. There was a 4 + right relative afferent pupillary defect. Visual field testing showed a dense central scotoma in the right eye (Fig. 1); the field of the left eye was normal. The patient was alert and oriented. Olfaction was decreased in the right nostril. The rest of the cranial nerves were normal. Motor, sensory, and reflex functions were all normal. The results of the general physical examination were normal. Tests of pituitary function, hematological values, and electrolytes, and the chest x-ray film were normal. A skull x-ray film showed demineralization and erosion of the planum sphenoidale and demineralization of the sella turcica (Fig. 2). A soft tissue mass encroached on the sphenoid sinus. A computed tomography (eT) scan revealed a large, irregular suprasellar and subfrontal mass with well-defined margins. It extended from the third ventricle into the right temporal lobe (Fig. 3). The medial portion of the mass was homogeneously enhanced after injection of contrast material; the lateral portion contained a large cyst. Cerebral angiography showed the tumor to be moderately vascular with early venous drainage. Operatioll At right frontotemporal craniotomy, a huge, firm, extracerebral, greyish-pink tumor extended beneath the frontal lobe and in front of the temporal lobe. It was adjacent to the cavernous sinus, within the prechiasmatic cistern, and extended to the Sylvian fissure. Posteriorly, the tumor was contiguous with the lamina terminalis and inferior surface of the third ven- Journal of Clinical Neuro-opthalmology Rutka et al. figure 1. G"ldm,mn pt'rimt'trY sh,nvs a dl'nse central Selltoma in thl' right eyt'. The field of the It'ft eye i, normal. tricle. The tumor enveloped the right optic nerve and abutted on the left optic nerve. It was dissected cleanl~' off both optic nerves and the right-third and fourth cranial nerves, as well as the right-posterior, middle, and anterior cerebral arteries. Radical removal of the large extracerebral portion of the tumor was performed along the fairly well-demarcated plane between tumor and brain, but a small amount of tumor was left around the right lenticulostriate arteries and the undersurface of the third ventricle. Neuropathological Examination Light microscopy showed a cellular tumor with interspersed areas of degeneration and fibrosis. The cellular portion was composed of sheets of cells showing no cytoarchitectural pattern except for a rare luminal structure (true rosette; Fig. 4a) and an occasional perivascular arrangement of tumor cells. The cell nuclei were round to oval, with evenly dispersed chromatin and occasional amphophilic nucleoli. Cellular Figure 2. Lateral skull x-ray film reveals demineralization of the sella turcica (large arrow). The greater wings of the sphenoid bone are indicated by small arrows (film slightly rotated). A soft tissue mass can be seen extending intI) the sphenoid sinus. September 1985 195 Optic Neuropathy and Ependymoma Figure 3. Contrast-enhanced CT scan before operation. A large suprasellar mass extends from the anterior third ventricle into the right middle fossa. The lateral portion of the mass is cystic. pleomorphism was absent and mitoses were rare. Bielschowsky staining for neurofibrils was negative. Immunoperoxidase staining with glial fi.brillary acid protein was positive, indicating eIther an astrocytic or ependymal origin. Electron microscopy showed predominantly polygonal cells with blunt cytoplasmic processes, which abutted the basement membranes of blood vessels in some areas. Intracytoplasmic filaments measuring 8-10 nm were aggregated into loose bundles or randomly arrayed. Occasional cilia with basal bodies were seen (Fig. 4b). These hght- and electron-microscopic features are characteristic of ependymomas. Postoperative Course A CT scan 1 month after surgery showed a sma!1 a~ount of residual tumor along the ante. roInfeno~ aspect of the third ventricle (Fig. 5). Vlsu~1 aCUIty. was reduced to finger counting at 6 ft In the nght eye, but acuity and field remained normal in the left eye. Lumbar puncture 1 month after operation showed normal cerebrospinal fluid (CSF) protein concentration and no tumor cells in the cytospin fraction. Two 196 months after operation, whole-brain irradiation of 5,000 rad was delivered in 25 fractions over 5 weeks using a 20-MeV Linear Accelerator. Care was taken to encompass the base of the skull, parasellar structures, the ethmoid and sphenoid sinuses, and to exclude the left eye from the field. Eighteen months after operation the patient remained neurologically normal, except that the impaired vision in the right eye remained unchanged. Discussion Compressive optic neuropathies are usually caused by lesions of the intracranial or intracanalicular portions of the optic nerves. 2,3 Early compression of the nerve causes a distinct syndrome of minimally decreased visual acuity, impaired color perception, an afferent pupillary defect, and a normal-appearing optic disc. 3 Failure to recognize incipient optic nerve compression may lead to profound visual loss and eventual irreversible atrophy.4 The most common compressive lesions are meningioma, pituitary adenoma, giant supradinoid aneurysm, and craniopharyngioma. Astrocytic hamartomas i,n children and malignant astrocytomas In adults" are glial neoplasms that arise within the optic nerve. O'Connor and Smith6 documented bitemporal field defects caused by chiasmal infiltration with a malignant ependymoma (ependymoblastoma). Primary gliomas of brain parenchyma occasionally compress or Invade the optic nerve. I We are not aware of other cases of optic neuropathy secondary to compression of the intracranial optic nerve by an ependymoma. Ependymomas comprise approximately 5% of all intracranial !?liomas. 7 They usually occur in relation to the tourth ventricle. 8- 11 Supratentonal ependymomas most commonly arise adjacent to the trigone of the lateral ventriclel2 but can tak~ origin from ependymal cell rests that ar.e not In continuity with the ependymal lining at the ventricles. lll4 Third-ventricle ependymomas are rare; they usually occur in the posterior halfl~ of the' ventricle and cause obstruction of CSF pathways.lo Ependymomas in the ~n~erior third ventricle tend to be large and cyStic. In one reported case,6 an ependymoblastoma presented as a third-ventricle mass t~at involved the chiasm; it responded tranSIently to radiotherapy and then to chemo~ h~rapy.b The tumor in our patient was unusual In ItS apparent origin from the floor of the third ventricle, its massive extracerebral extension, and its tendency to envelope blood vessels and cranial nerves. Journal of Clinical Neuro-ophthalmology Rutka et al. (b) Figure 4. a: Photomicrograph shows tumor cells with round to oval nuclei. A true rosette is demonstrated at the arrow (H&E, x 119). b: A cilium (large arrow) and a basal body (small arrow) are evident. Intr,lCytoplasmic filaments measuring 8-10 nm are loosely aggregated into bundles (electron microscopy. x 5.500 original m,1gnification). Another distinctive feature of this neoplasm was erosion of the planum sphenoidale, evident on skull x-ray films and presumably caused by direct pressure by the exophytic growth. While such bony changes are frequently associated with meningiomas arising from the planum, localized demineralization of the skull by an in- September 1985 tracranial glioma is uncommon. One reported ependymoblastoma 16 arose from the frontal lobe, invaded dura, and eroded the adjacent skull, but we are not aware of other cases of low-grade ependymoma causing bony changes. Although supratentorial ependymomas are more often malignant than their infratentorial 197 Optic Neuropathy and Ependymoma Figure S. Postoperative contrast-enhanced CI scan shows a small amount of residual tumor at the anteroinferior aspect of the third ventricle, counterparts, 10,1 \,17,18 there was no cytologic anaplasia to suggest an ependymoblastoma in our patient. Albeit histologically benign, the tumor displayed aggressive exophytic growth surrounding blood vessels and cranial nerves. Current evidence suggests that patients with ependymomas benefit from cranial irradiation 17,19 Radiation to the entire craniospinal axis is probably indicated only if spinal seeding by tumor cells can be confirmed. 19 In the absence of spinal seeding, the lO-year survival rate is about 75%11,18,19 after combined surgery and radiotherapy, as performed in our patient. References 1. Jefferson, G,: On compression and invasion of the optic nerves and chiasm by neighboring gliomas. TrailS, 0l'hthall11ol, Soc. UK 65: 262-304, 1945, 2. Kayan, A" and Earl, C. J,: Compressive lesions of the optic nerves and chiasm-pattern of recovery of vision following surgical treatment. Braill 98: 13-28, 1975, 3. Knight, C. L., Hoyt, W. F., and Wilson, C. B.: 198 Syndrome of incipient prechiasmal optic nerve compression. Arch, Ophthalmol. 87: 1-11, 1972. 4. Little, H. L., Chambers, J. W., and Walsh, F. B.: Unilateral intracranial optic nerve involvement: neurosurgical significance. Arch. Ophthalmol. 73: 331-337, 1965. 5. Hoyt, W. F" Meshel, L. G" Lessel.1, S., Schat~, N. j" and Suckling, R. D.: MalIgnant Optic glioma of adulthood. Brain 96: 121-132, 1973. 6. O'Connor, P., and Smith, J. L.: Chlasmal ependymoma, Ann, Ophthalmol. 9: 1424-1428, 1979. 7, Rubinstein, L. J.: Tumours of the CNS, senes 2. Armed Forces Institute of Pathology, Washington, DC 1972, pp. 104-126. 8, Barone, B, M., and Elvidge, A, R.: Ependymomas- a clinical survey, f. Neurosurg. 33: 428438, 1970. 9. Broussalian, S. L.: Intracranial ependymochoroidal tumours: an analysis of 53 cases. Bull. LA Neuro!. Soc. 23, 119-129, 1953. 10. Fokes, E, c., and Earle, K. M.: Ependymomas: clinical and pathological aspects. f. Neurosurg. 30: 585-594, 1969. 11. Mork, S, J" and Loken, A. c.: Ependymoma-a follow up study of 101 cases, Cancer 40: 907-915, 1977. 12, Shuman, R. M., Ellsworth, C. A., and Leech, R. W.: The biology of childhood ependymomas. Arch. Neuro!. 32, 731-739, 1975. 13. Russel, D. S., and Rubinstein, L. J.: Pathology of TIII1/ours of the Nen'ous Sl/stem (4th ed.), Williams & Wilkins, Baltimore, 1977, pp. 204-219. 14, Swartz, D., Zimmerman, R. A., and Bilaniuk, L. T.: Computed tomography of intracranial ependvmomas, Radiology 143: 97-101, 1982. 15, Arendt A.: Epend~'momas. In Tumours of tile Brain alld Skull. Halldl'ook of Clillital Neurology, Vinker, P, j., and Bruvn, G. W" Eds., North Holland Publishing Co.', Amsterdam, 1975, Chap. 5, pp. 105-150, 16. Meredith, J. M., and Sahyoun, P. F.: Ependymoblastoma grossly eroding and involving overlying dura and skull. /. Nt?urosurg. 8: 214-219, 1951, 17. Chin, H. W., Maruyama, Y., Markesbery, W., et al.: Intracranial ependymoma-results of radiotherapy at the University of Kentucky. Callcer 49: 2276-2280, 1982, 18, Dohrmann, G. J., Farwell, j. R., and Flannery, J. T.: Ependymomas and ependymoblastomas in children. /. Nellrosurg, 45: 273-283, 1976. 19, Salazar, O. M., Castro-Vita, H., and VanHoutte, P,: Improved survival of cases of intracranial ependymoma after radiation therapy. f. NeuraslIrg. 59: 652-659, 1983. journal of Clinical Neuro-ophthalmology |
