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Show © 1989 Raven Press, Ltd., New York Cavernous Angiomas of The Anterior Visual Pathways W. Hassler, M. D., J. Zentner, M. D., and H. Wilhelm, M. D. Three patients with cavernomas of the optic nerve, chiasm, or optic tract are presented. All suffered progressive visual loss due to local hemorrhage and the spaceoccupying effects of the vascular malformation. Computed tomography scans revealed small lesions with mild contrast enhancement in the suprasellar and parasellar cisterns, whereas angiography was unremarkable. Magnetic resonance imaging was helpful in our cases both for diagnosis and for planning surgical approach, showing typical signs of cavernomas as confirmed by subsequent surgery and histological examination. The clinical and intraoperative findings are presented. Key Words: Cavernous angioma- Optic nerve- Optic chiasm- Optic tract. From the Departments of Neurosur~ ery ( W. H., J. Z.) and Neuro- Ophthalmology ( HW). Medical School, University of Tilbingen. Federal Rt'public of Germanv. Addr"" (,,,,,"," ' ndeno.' and reprint rt'l. juests to Prof. Dr. W. ":: ... : 1' 1."", ' '.. '."""."~' · rv. Medical School, Cal- 760 Cavernous angiomas ( cavernomas) account for 5- 13% of all intracranial vascular malformations ( 1) and are known to occur in brain tissue ( 2,3), in the ventricles ( 4,5), and in the orbit and eye ( 6,7). In recent years, these tumors have been most frequently diagnosed by magnetic resonance imaging ( MRl), which typically shows a high- signal lesion on Tl- weighted images with a surrounding irregular dark rim, a finding that is more evident on T2- weighted images ( 8- 10). Cavernomas arising from the anterior visual pathways are rare and, to date, only three such cases have been reported ( 11- 13). During the last year, we observed three patients with cavernomas of the optic nerve, chiasm, or optic tract. As complete surgical removal was possible in all patients, we are encouraged to report our experience. CASE REPORTS Case 1 Clinical Features Three years ago, a 24- year- old woman had her first sudden attack of headaches associated with a permanent defect of the right nasal visual field. The visual disorder improved spontaneously within 4 weeks, and there were no abnormalities until March 1987. At this time, she again experienced sudden headaches associated with a right nasal hemianopsia. Because of persistence of the ophthalmological disturbances she was admitted to our department in November 1987. Neuroophthalmological examination revealed an incomplete right nasal hemianopsia and a small relative scotoma of the upper temporal quadrant on the left ( Fig. 1). Visual acuity was 0.8 ( 16/ 20) in both eyes. The right optic nerve was partially atrophic and there was a relative afferent pupillary defect on the right. OPTIC CAVERNOMAS 161 FIG. 1. Case 1. Visual fields before surgery: Incomplete nasal hemianopsia on the right side and small relative scotoma of the upper temporal quadrant on the left side. LEFT RIGHT Radiological Findings The computed tomographic ( CT) scan showed a well- demarcated, hyperdense lesion 5 mm in diameter in the right suprasellar cistern. There was no enhancement with contrast medium. Angiography was inconspicuous. Magnetic resonance imaging ( MRI) revealed a low- signal lesion on the Tl- weighted images and an irregular, ring- shaped lesion on the T2- weighted images, as is typical of cavernoma. Suspecting compression of the optic nerve by the lesion, surgery was performed on November 19, 1987. Intraoperative Findings The right optic nerve was found to be stained yellow, which suggested prior bleeding. On its lateral and caudal side there was an exophytic angiomatous tumor ( Fig. 2). Pseudogliosis was found around the vascular malformation, facilitating its removal. Histological examination of the specimen revealed a cavernous angioma with signs of prior hemorrhage. Postoperative Course The postoperative course was uneventful. Visual fields showed a complete nasal hemianopsia on the right side and an incomplete upper temporal quadrantanopsia on the left side ( Fig. 3). Visual acuity was 0.6 ( 12120) on the right and 0.8 ( 16/ 20) on the left. Visual acuity improved to 0.8 on the right side after 1 month. Disc pallor was more distinct postoperatively and is now visible on both sides. Case 2 Clinical Features A 16- year- old male patient suffered slowly progressive reduction of visual acuity that was pro-nounced on the right side and lasted for 2 years. Neuro- ophthalmological examination on admission to our department revealed a visual acuity of 0.25 ( 5/ 20) on the right and 0.8 ( 16/ 20) on the left side. There was a relative afferent pupillary defect on the right side. Visual fields showed an asymmetric defect with upper temporal quadrantanopsia on the left and complete loss of the nasal side and constriction of the remaining field in the right eye ( Fig. 4). The optic discs showed marked atrophy on the right and beginning atrophy on the left. Other neurological findings were normal. Radiological Findings The CT scan showed a contrast- enhanced and partly calcified lesion of 10 mm diameter in the suprasellar and right parasellar cistern, whereas angiography was unremarkable. Magnetic resonance imaging showed a low- signal lesion with a surrounding dark rim on T2- weighted images above and to the right of the optic chiasm. Intraoperative Findings Surgery was performed on August 16, 1988, using a pterional approach. The optic chiasm was found to be yellow in color and distended. The prominent chiasm showed multiple black spots on its upper surface, representing enlarged veins of the cavernoma. The angiomatous tumor was localized to the right superior aspect of the chiasm ( Fig. 5). The tumor was removed completely, but additional trauma to the right optic nerve was unavoidable owing to multifocal extension of the tumor between the optic nerve fibers. Histological examination confirmed the diagnosis of a cavernoma. Postoperative Course Postoperatively, the right eye became amaurotic, whereas visual acuity and visual field on the left side remained unchanged. JClin NCllro- ophthnlmol, Vol. 9. No. 3. 1989 162 W. HASSLER ET AI. FIG. 2. Case 1. Intraoperative findings: Cavernoma at the lateral and caudal aspect of the right optic nerve ( arrow). A: Situs before removal of the cavernoma. B: Sectional enlargement of A. C: Situs after removal of the cavernoma. CH., optic chasm; N. II!., left optic nerve; N. llr., right optic nerve; ICAr., right internal carotid artery; A1r., A1- portion of the right anterior cerebral artery; MCA, middle cerebral artery. Case 3 Clinical Features In December 1987, a 35- year- old man suffered from headaches for the first time. The initial CT scan showed a subarachnoid and right- sided, temporomedial space- occupying hemorrhage. Neuroophthalmological examination after recovery revealed a relative homonymous visual field defect on the left. Visual acuity was 1.0 ( 20/ 20) on both sides. Optic discs were normal. No relative afferent pupillary defect was present. Radiological Findings A contrast- enhanced lesion 10 mm in diameter was found in the right suprasellar cistern on CT scan. An aneurysm was originally suspected. However, no vascular malformation was found on angiography, which was repeated twice. On Tlweighted images, MRI showed an isointense, irregularly confined space- occupying lesion in the right lateral wall of the third ventricle. On T2weighted images, a peripheral hypointense rim typical of cavernomas was visible. Intraoperative Findings Surgery was performed in April 1988, using a right- sided pterional approach. The right optic tract was found to be colored yellow on its lateral and dorsal aspect as a sign of older bleeding. The lesion was accessible above the carotid bifurcation, and extended from the medial aspect of the right optic tract to the wall of the third ventricle. The optic tract showed black spots at its upper surface representing enlarged veins of the cavernoma ( Fig. 6). The tumor was well circumscribed and was / / I/ / I , j-", .: i--. i! r I r FIG. 3. Case 1. Visual fields after surgery: Complete nasal hemianopsia on the right side and incomplete upper temporal quadrant anopsia on the left side. ,"' . ' 1 I: , III , Clin Neuro · ophlhalmol, Vol. 9, No. 3, 1989 FIG. 4. Case 2. Visual fields before surgery: Complete loss of nasal visual field and constriction of the remaining field on the right side; asymmetric defect with upper temporal quadrantanopsia on the left side. OPTIC CAVERNOMAS \ C ,\ I .. ' ", i, ii LEFT ., ~~__----- l -----" RIGHT 163 90 ~ [ j completely removed without substantial bleeding. Histological examination of the specimen confirmed the diagnosis of a typical cavernoma with prior hemorrhage. Postoperative Course The postoperative course was uneventful. The visual field was nearly normal. Only a slight defect remained, and visual acuity was 1.2 ( 24/ 20) on both sides. DISCUSSION Tumors of the anterior visual pathways are rare and predominantly represent meningiomas and gliomas. Although the main clinical symptom of both is slowly progressive visual disturbance, these tumors can easily be diagnosed by CT scan. This allows variable surgical management, which was quite active in the first case and cautious in the second. To date, three cases of cavernomas have been reported with this localization ( 11- 13). All were diagnosed by surgical exploration. In the cases presented here, preoperative diagnosis was possible with MRI, which showed cavernomatypical features ( 8- 10,14) of the lesions. The question arises of whether cavernomas in this delicate localization should be treated surgically. In our opinion, this is primarily a question of the natural history of these vascular malformations. The cases observed in retrospect mainly tended toward a deteriorating neurological condition over years ( 2,15). In the majority of untreated patients reported by Giombini and Morello ( 15), epileptic or other neurological disorders worsened, in part with fatal outcome owing to recurrent hemorrhage. However, no exact data exist on the risk of incidence of neurological disorders in untreated cavernomas ( 16). One can expect more experience in this question with more frequent diagnosis of these tumors using MR!. The patients presented here had a history of progressive visual loss over the course of 4 months to 3 years. Local hemorrhage was present in all cases, as confirmed by surgery and histological examination. In addition, bleeding with mass effect was the initial symptom in one case. Thus, we agree with other investigators ( 3,16) that cavernomas that have become symptomatic should be treated FIG. 5. Case 2. Intraoperative findings: Cavernoma at the right aspect of the optic chiasm ( arrows). Situs before ( A) and after ( B) removal of the cavernoma. Abbreviations as in Fig. 2. JGin Neuro- ophthalmol, Vol, 9, No. 3, 1989 164 W. HASSLER ET AI. FIG. 6. Case 3. Intraoperative findings: Cavernoma at the cranial and medial aspect of the right optic tract ( arrow). Note the black spots at the upper aspect of the optic tract representing enlarged veins of the cavernoma. Situs before ( A) and after ( B) removal of the cavernoma. Abbreviations as in Fig. 2. surgically, even if mild neurological deterioration may be expected. Owing to earlier hemorrhage, our patients were obviously at high risk of progressive visual loss if the lesion had remained untreated. While surgical therapy of cortical or subcortical cavernomas is usually simple because of the sharp demarcation of cavernomas, with minimal or no bleeding ( 17), treatment of cavernomas of the anterior visual pathways and chiasm is more delicate owing to close anatomical relationships to essential structures. Our results show that despite these in-herent problems, complete microsurgical removal is possible, leading even to postoperative improvement of visual disturbances, as observed in one patient. To the best of our knowledge, Maruoka et a1. ( 12) reported the only case with complete surgical removal of an optic nerve cavernoma. However, excision provides the security that no further complications should be expected. REFERENCES 1. McConnick WF, Schochet SS. Atlas of cerebrovascular disease. Philadelphia: Saunders, 1976. 2. 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Account of fourteen personal cases and review of the literature. Aria Neuroclrir ( Wien) 1978; 40: 61- 82. 16. Wilkins RH. Natural history of intracranial vascular malformations: a review. Neurosurgery 1985; 16: 421- 30. 17. Rengachary SS, Kalyan- Roman UP. Other cranial intradural angiomas. In: Wilkins RH, Rengachary SS, eds. Neurosurgt'ry. New York: McGraw- Hili, 1985: 1465- 73. |
