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Show ,. C/ill. NclII'o-ophtlltllll/ol. 5: 112· lIe;, IlJHe; (i,) 1985 Raven Press, New York Sarcoidosis of the Tentorium with Cortical Blindness J. MICHAEL rOWERS, M.D. Abstract Sarcoidosis rarely involves the visual system posterior to the chiasm. A 55-year-old woman presented with fluctuating bilateral macular-sparing homonymous hemianopsia. The computed tomographic scan revealed an extensive contrast-enhancing density involving the tentorium, posterior falx, and adjacent medial occipital lobes and cerebellum. Spinal fluid studies revealed a mixed cellular response, and a biopsy of the meninges established the diagnosis of sarcoidosis. Ultimately, vision was lost, despite chronic steroid therapy. The presumed mechanism of visual loss is infiltration of the occipital lobes by meningeal granulomas, possibly with coexistent vascular occlusion. One-fourth of patients with sarcoidosis have visual involvement, most commonly of ocular origin. Postchiasmal syndromes are rare, and visual field loss due to involvement of the visual cortex has not been reported previously. One such patient, in whom fluctuating cortical visual loss resulted from granulomatous infiltration of the occipital cortex from the adjacent tentorium and falx, is described here. Case Report In May 1980, shortly after a minor automobile accident, a 54-year-old woman began having headaches and visual blurring. Her past health had been unremarkable except for mild hypertension of several years' duration. While hospitalized, she described a loss of all light perception that lasted about 1 h. When vision returned, she was found to have a right homonymous hemianopsia with macular sparing. The ocular examination was unremarkable. A computed tomographic (CT) scan of the head demonstrated an extensive plaque-like enhancing density involving the tentorium, pos- Dr. Powers is in private practice in Phot'ni:\, Arizon,L Write for rCl'rint, to: J. M. Powers, MD, 525 N. l~th St., Suite 6U2, Phoenix, AZ IlSU06, U.S.A. 112 terior falx, and adjacent occipital cortex and cerebellum. The ambient and quadrigeminal cisterns were obliterated. Cerebrospinal fluid (CSF) examination revealed 17 white cells with 15'!r segmented neutrophils, 70O/C lymphocytes, and 15'fr large mononuclear cells. The CSF protein level was 56 mg'7c and the glucose level was 59 mg'7c. Cerebral angiography was normal. No diagnosis was established and the patient did not seek further medical evaluation until February 1981, when she again developed complete loss of vision. Central vision gradually returned. Her corrected visual acuity was 20/25 OU and her ocular examination remained normal. Confrontation visual fields revealed bilateral homonymous hemianopsias with macular sparing. Vision returned, and, when she was hospitalized, Goldmann perimetry demonstrated a complete right homonymous hemianopsia with macular sparing. The left visual field was intact. A chest x-ray film showed symmetrical hilar adenopathy, which had not changed for several years. A CT scan documented persisting enhancement of the tentorium. Some ventricular dilatation had developed since the 1980 scan. The Westergren sedimentation rate was -18 mm/h. The blood count and panel of serum chemistries were normal. The FTA and VORL were nonreactive. The CSF showed 30 white cells with 1O'7c neutrophils, 62'7c lymphocytes, and 28'7c large monocytes. The protein level was 137 mg'7c and the glucose level was 56 mg'i(, \,\,ith a simultaneous blood glucose level of 123 mg'7c. The CSF cytology and culture results were negative. A posterior fossa craniotomy revealed granulomatous tissue encasing the tentorium and posterior falx and infiltrating the medial occipitallobes. Pathologic examination confirmed the presence of numerous microgranulomas composed ot epithelioid histiocytes and occasional multinucleated Langhan's giant cells, consistent ~ith s.arcoidosis. Cultures of the biopsy specImen tor fungi and tuberculosis were negative. A diagnosis of neurosarcoidosis was made and the patient was treated with prednisone, 80 mg! day. After 1 month, the dosage was gradually reduced to 80 mg on alternate days. A repeat CT scan in September 1981 showed that the ventricles had returned to normal size and the pattern of tentorial enhancement was slightly less pronounced. During this time there was a persistent right homonymous hemianopsia with macular sparing. The patient's maintenance prednisone dosagt' W,lS -i0 mg on altl'rnate days. In Jalluar~' 1982, the patient l'xpl'rienced the abrupt onset of tlashing lights ,1l1d zigzag lines in her left yisual field. Thest' pt'rsisted ior 2 days and were assl1Ciated with gr,ldually evolving loss of Yisil1l1 to the left. Goldmann perimetry demonstrated a complett' kft homonymous hemianopsia, induding Illss llf macular vision. The right homon~'n1l1usl1t'mianopsia with macular sparing persisted. Thus, vision was limited to 5° to the right of the vertical midline in each eye. External e\.amination again revealed no evidence of ocular sarcoidosis. A repeat CT scan demonstrated persistent enhancement in the region of the tentorium and posterior falx, unchanged from previous examinations (Fig. 1-3). There was no evidence of occipital lobe infarction. CSF e\.amination revealed 2 white cells, a glucose level of 65 mg(lr, and a protein level of 36 mgCC. The angiotensin-converting enzyme assay was measured for the first time and prov'ed to be normal. Cerebral angiography was normal. with no vascular occlusion or abnormal vascularity in the region of the occipital lobes. The prednisone dosage was increased to 80 mg/ day and, over the course of 1 week, there was a gradual return of vision in the left visual field. The prednisone dosage was slowly adjusted to 80 mg on alternate days. Despite continued steroid use, she again lost vision, with preservation of only 5° of central vision bilaterally. In mid-1983, after 1 year without return of vision, she elected to discontinue the prednisone. There has been no change on subsequent clinical examinations and CT scans through April 1984. Powers Discussion The central nervous system is affected in 5(~, oi patients with sarcoidosis. J While most patil'nts have multisystem disease, some, like the patient described here, have predominantly or exclusively central nervous system involvement. ~.l Most visual symptoms of sarcoidosis derive irom ocular disease. Anterior and posterior uveitis, vitreous opacities, perivascular sheathing, and retinal and choroidal exudates may be encountered. ~ The nerve head can be directly involved by a granuloma. Disc edema may result from increased intracranial pressure or as a reaction to the uveitus. Retrobulbar visual system involvement may result from three basic mechanisms: 1) direct infiltration by the basilar granulomatous meningitis, 2) compression by a granulomatous tumor, and 3) infarction due to angiitis. Visual symptoms might also arise from papilledema or from distortion of the visual system by hydrocephalus due to obstruction of CSF pathways by meningeal granulomas. The most common neurologic manifestations of sarcoidosis result from the basilar meningitis. Local infiltration into the cranial nerves may produce multiple cranial nerve palsies. Opt{c nerve and chiasmaI damage can result from this mechanism.' The optic nerve and chiasm may also be damaged by extrinsic compression irom a discrete granulomatous tumor. t> Byrne and Lawton? reported a case of sarcoidosis with visual loss due to papilledema resulting from dural sinus thrombosis. The CT scan showed enhancement of the tentorium and the cerebral angiogram confirmed occlusion of the straight sinus and left lateral sinus. There was no evidence of occipital lobe involvement. Caplan et al. H recently emphasized that basilar meningitis can be associated with a vasculitis, with resultin~ ischemic damage. Neuro- Figure 1. UIll'nh,lncc'd l1<lrizllnl.J1 CT scans demonslr,lling subtll'. inl'rl'.Jsed densilV in the n'gion of the ll'nlorium. June 1985 113 Sarcoidosis of thl' Tl'ntoriulll Figure 2. Horizontal CT scans showing a contrast-enhancing densit\' Involving and adjacent to the tentorium. logic involvement in these cases tends to be especially severe. The authors labeled this the angiitic form of sarcoidosis and noted that intraocular involvement paralleled the intracranial disease in all cases. They speculated that some of the transient symptoms encountered in neurosarcoidosis may have a vascular mechanism. Homonymous visual field loss because of damage to the postchiasmal visual radiation has been a rare occurrence in sarcoidosis. Everts" described a patient with a right homonymous hemianopsia owing to a left occipital lobe granulomatous tumor. The present case is unique, since occipital lobe involvement resulted from direct infiltration of the granulomatous tissue associated with the basilar meningitis. The meningeal reaction extended to the tentorium and adjacent falx. Involvement of these structures provided the framework for extension into the occipital lobes. Our patient's course was characterized by dramatic fluctuations in visual field involvement. The early fluctuations occurred before steroid therapy, demonstrating that spontaneous improvement is possible. While corticosteroids remain the drugs of choice, improvement may be incomplete or transient. Most patients with sarcoid meningitis continues to deteriorate despite steroid therapy.l Given the potential for spontaneous improvement, an apparent response to therapy must be interpreted with some caution. L'ltimately, our patient sustained severe loss of \'ision, with bilateral homonymous hemianopsia with macular sparing. Her symptoms and the CT abnormalities have not changed despite cessation of steroid 114 Orlll1cll C r Slcllb Jl'Il11Jllslrdllllg till' lllntrdsl-enhancIng denslt\' in tilt' region of the tentorium and posterior falx. Illurn,ll lli Clinical Nl'uro-ophthalmology therapy. Clearly, alternatives to stL'roid therapy are desirable. Recentlv, low-dose, wholl'-br,1in irradiation has been sllggested. Iii The fluctuating visual symptoms in the present case suggest a possible vascul.1r Illl'chanism, consistent with the angiitic process proposed b~' Caplan t't al. s Unlikt' their caSl'S, our patient never demonstr,1ted l)cul.1r s.1rcoidosis. Two angiograms failed to show l'\'idence of vascular involvement. Patholl)gical e"amination ma~' be required to document the presence of angiitis. Indeed, the e"istencl' of ,1 discrete angiitic form of s.1rcoidl)sis is question,1blc, since all cases so classified have had ,1ctive b,1sil.1r meningitis. The vascular invl)lvement may simply retlect the local inflammatory effect of the meningitis and may have a mechanism similar to the vasculitis that is encountered in other forms of acute and chronic meningitis. Igarashi et .11. 11 speculated that the vascular occlusions occurring in acute meningitis result from vasospasm, with a mechanism similar to that encountered in subarachnoid hemorrhage. Thus, damage to structures adjacent to the granulomatous meningitis may result from the combination of local granulomatous infiltration and inflammatory vascular occlusion. Although -a rare cause of postchiasmal visual loss, sarcoidosis must be considered when a homonymous hemianopsia is associated with a pattern of chronic meningitis. Evaluation of unexplained chronic, fluctuating visual loss should include a CSF examination. The discovery of pleocytosis, or abnormal CT enhancement in the region of the tentorium indicates the presence of a local inflammatory process, requiring consideration of neurosarcoidosis. June 1985 Powers Acknowledgment james Corbett, M.D., critically reviewed the manuscript. References l. Delaney, P.: Neurologic manifestations in sarcoidosis. All/I. Illterl!. Med. 87: 336~345, IlJ77. 2. Cariski, A. T.: Isolated CNS sarcoidosis, lAMA 245: 62 - 63, IlJH 1. 3. Cahill, D. W., and Salcman, M.: Neurosarcoidosis: a review of the rarer manifestations. SurX' Nel/ml. 15: 204-211, IlJHI. 4. Turner, R. G., james, D. G., Friedmann, A. 1., and Vijendram, M.: Neuro-ophthalmic sarcoidosis. Rr. f. Ophtllill. 59: 657-662, IlJ75. 5. Tang, R. A., Grotta, J. C, Lee, K. F., and Lee, Y. E.: Chiasma I syndrome in sarcoidosis. Arch. Ophthallllol. 101: 1069-1073, 1983. 6. Slavin, M. L., and Glaser, j. S.: Optic neuropathy and cerebral sarcoidosis. f. Clill. Neuro. Opfhallllol. 3: 259-262, 1983. 7. Byrne, J. V., and Lawton, C A.: Meningeal sarcoidosis causing intracranial hypertension secondary to dural sinus thrombosis. Br. f. Radio!. 56: 755-757, 1983. 8. Caplan, L., Corbett, J., Goodwin, J., Thomas, C, Shenker, D., and Schatz, N.: Neuro-ophthalmologic signs in the angiitic form of neurosarcoidosis. Nel/rology (Clel'elalld) 33: 1130-1135, 1983. 9. Everts, W. H.: Sarcoidosis with brain tumor. TrailS. Alii. Nel/rol. Assoc. 72: 128-130, 1947. 10. Grizzanti, J. N., Knapp, A. B., Schecter, A. J., and Williams, M. H.: Treatment of sarcoid meningitis with radiotherapy. Alii. f. Med. 73: 605608, 1982. 11. Igarashi, M., Gilmartin, R. C, Gerald, B., Wilburn, F., and Jabbour, J. T.: Cerebral arteritis and bacterial meningitis. Arch. Nel/rol. 41: 531- 535, 1984. 115 |
