Cavernous Malformation of the Optic Nerve and Chiasm: Prompt Suspicion and Surgery Matter

Cavernous malformations (CMs) of the optic nerve and chiasm are extremely rare, accounting for less than 1% of all intracranial CMs. Acute, subacute, or progressive visual loss from CM may occur with or without hemorrhage. Prompt surgical excision of the CM offers the best hope to improve or stabilize vision. Given its rarity, optic nerve and chiasm CMs may not be readily suspected. We provide 3 cases of optic nerve and chiasm CM, highlighting key neuroimaging features and the importance of expedited intervention

Original Contribution Section Editors: Clare Fraser, MD Susan Mollan, MD Cavernous Malformation of the Optic Nerve and Chiasm: Prompt Suspicion and Surgery Matter Maja Kostic, MD, PhD, Prem S. Subramanian, MD, PhD, Steven F. Falcone, MD, MBA, Seif Tarek El-Swaify, MD, Samir Sur, MD, Smiljana Spasic, MD, Neil R. Miller, MD, Jacques J. Morcos, MD, Byron L. Lam, MD Background: Cavernous malformations (CMs) of the optic nerve and chiasm are extremely rare, accounting for less than 1% of all intracranial CMs. Acute, subacute, or progressive visual loss from CM may occur with or without hemorrhage. Prompt surgical excision of the CM offers the best hope to improve or stabilize vision. Given its rarity, optic nerve and chiasm CMs may not be readily suspected. We provide 3 cases of optic nerve and chiasm CM, highlighting key neuroimaging features and the importance of expedited intervention. Methods: Case records of the neuro-ophthalmology clinics of the Bascom Palmer Eye Institute and the University of Colorado, and literature review of reported cases of optic CM. Results: A 49-year-old woman reported acute progressive painless vision loss in the right eye. MRI showed a suprasellar mass with heterogeneity in signal involving the right prechiasmatic optic nerve. Surgical excision of the CM 5 days after onset of visual loss improved vision from 20/300 to 20/30. A 29-year-old woman with acute painless blurred vision in the right eye had anterior chiasmal junctional visual field defects corresponding to a heterogeneously minimally enhancing mass with blood products enlarging the optic chiasm and proximal right optic nerve. Surgical excision of the CM 8 weeks after onset of visual loss improved vision from 20/40 to 20/15 with improved visual fields. A 33-yearold woman with a history of familial multiple CMs, diagnosed at age 18, reported new-onset severe headache folBascom Palmer Eye Institute (MK, BLL), University of Miami, Miami, Florida; Sue Anschutz-Rodgers UCHealth Eye Center and Departments of Ophthalmology, Neurology, and Neurosurgery (PSS), University of Colorado, Denver, Colorado; Departments of Radiology (SFF) and Neurological Surgery (STE, S. Sur, JJM), Pathology (S. Spasic), University of Miami, Miami, Florida; and Wilmer Eye Institute (NRM), Johns Hopkins University School of Medicine, Baltimore, Maryland. The authors report no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www. jneuro-ophthalmology.com). Address correspondence to Byron L. Lam, MD, Bascom Palmer Eye Institute, University of Miami, 900 NW 17th Street, Miami, FL 33136; E-mail: [e-mail] 108 lowed by blurred vision. MRI showed a hemorrhagic lesion of the optic chiasm and right optic tract. She was 20/20 in each eye with a reported left superior homonymous hemianopia. No intervention was recommended. Vision of the right eye worsened to 20/400 2 months later. The patient was followed over 13 years, and the MRI and visual function remained unchanged. Literature review yielded 87 optic CM cases occurring across gender and nearly all ages with visual loss and headache as the most common presenting symptoms. Optic chiasm is the most common site of involvement (79%). Nearly 95% of reported CM cases were treated with surgery with 81% with improved vision and 1% with worsened vision. Conclusion: MRI features are critical to the diagnosis of optic nerve and chiasm CM and may mimic other lesions. A high index of suspicion by the neuro-ophthalmologist and neuroradiologist leads to early recognition and intervention. Given optic CM displaces and does not infiltrate neural tissue, expedited surgical resection by a neurosurgeon after consideration of other diagnostic possibilities improves visual function in most cases. Journal of Neuro-Ophthalmology 2022;42:108–114 doi: 10.1097/WNO.0000000000001238 © 2021 by North American Neuro-Ophthalmology Society C avernous malformations (CMs), also called cavernomas, cavernous angiomas, or cavernous hemangiomas, are clusters of abnormal tortuous and thin-walled blood vessels that occur in the brain, spinal cord, dura, or cranial nerves. The prevalence of CM is approximately 0.4%–0.5% (1,2), according to autopsy and MRI series (3–5). CMs can appear at all ages but usually occur in the third to fourth decade of life with no gender preference. CMs consist of thin-walled vascular channels lined by a single layer of endothelium, which may be calcified, and contain stagnated blood in varying degrees of thrombosis and degradation. CMs of the anterior visual pathway are extremely rare. The most common site is at or near the optic chiasm with involvement of the optic chiasm, optic nerve, and/or optic Kostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution tract, often resulting in acute, subacute, or progressive visual loss with or without headache or hemorrhage of the CM. Given its rarity, CMs of the optic nerve and chiasm are often misdiagnosed neuroradiologically, given that the MRI appearance may mimic craniopharyngioma, germinoma, optic glioma, meningioma, metastatic lesion, thrombosed or partially thrombosed aneurysm, or ectopic pituitary adenoma. We describe 3 patients with CMs involving the optic nerve, chiasm, and optic tract, highlighting key MRI diagnostic features critical to the diagnosis of suspected CM and the importance of expedited surgical excision as the best hope to improve or stabilize vision given optic CM displaces and does not infiltrate neural tissue and is resectable in most cases. We also performed a review of all reported optic CMs and provide a summary of demographics, presenting symptoms, CM location, intervention, visual acuity, visual field, and outcomes. CASE 1 A 49-year-old healthy woman developed acute progressive, painless vision loss in the right eye over 2 days. Bestcorrected visual acuity was 20/300 in the right eye and 20/ 20 in the left eye with a right afferent pupillary defect. Automated perimetry showed diffuse depression in the right eye and normal visual field in the left eye. The right optic nerve had mild diffuse pallor without edema with reduced mean OCT ganglion cell layer (GCL) thickness of 57 mm in the right eye, 74 mm in the left eye and retinal nerve fiber layer (RNFL) thickness of 65 mm in the right eye, 87 mm in the left eye, and the left optic nerve was normal. Orbit and brain MRI with gadolinium showed a 17 · 12 · 10-mm suprasellar mass with heterogeneity in signal encompassing the optic chiasm and right prechiasmatic optic nerve, separate from the pituitary gland and stalk (Fig. 1A). The abnormality was predominantly T1 isointense with areas of high FIG. 1. Case 1. A. T1W fat-suppressed coronal, B. T1W fat-suppressed coronal postcontrast, C. T2W coronal, D. T2W gradient-echo axial, and E. CT coronal at the level of the optic chiasm. There is expansion of optic chiasm eccentric toward the right with involvement of right prechiasmatic optic nerve. There are punctate regions of T1 hyperintensity central low T2 signal, rim of low signal on the gradient-echo sequence, patchy enhancement, and slight hyperintensity on CT scan. Findings suggestive of blood products in a mass that is consistent with but not pathognomonic of a cavernoma. No other regions of susceptibility were identified in the brain (images not shown). F. Cavernous malformation with characteristic “mulberry” appearance emerging from the lateral portion of the right optic nerve. G. After complete removal of CM, remaining, intact fibers of the right optic nerve course around the resection cavity; H. EVG special stain shows absence of elastic layer in venous type vessels (original magnification ·200). I. Visual acuity improved from 20/300 before surgery to 20/30 after surgery; automated perimetry 9 days after surgery shows persistent visual field defect in the right eye. J. Axial imaging through the brain 6 months after surgery at the level of the optic chiasm reveals no chiasmal mass or abnormal enhancement. Kostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 109 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution T1 signal and heterogeneous T2 signal. There is a thin rim of low signal that is difficult to appreciate on the nondedicated images of the brain. Orbital CT with contrast showed no calcification. Right supraorbital craniotomy with lesion resection 5 days after onset of symptoms revealed intraoperative appearance and histopathology consistent with a CM (Fig. 1H). Postoperatively, the right eye improved significantly from 20/300 to 20/30 over weeks with improved visual field (Fig. 1I). Optic disc pallor of the right eye persisted and showed a decrease of 5 mm in mean OCT GCL and a decrease of 10 mm in OCT RNFL thickness compared with initial presentation while the left eye showed no changes. MRI 7 months after surgery showed some mild distortion of the chiasm and right prechiasmatic optic nerve with removal of the mass and residual low T2 signal most compatible with hemosiderin (Fig. 1J). CASE 2 A 29-year-old previously healthy woman awoke with painless blurred vision in her right eye. She had visual acuity 20/40 in the right eye and 20/20 in the left eye with a right relative afferent pupillary defect. Color vision was reduced in both eyes, right more than left. Automated perimetry demonstrated central and inferior (nasal worse than temporal) depression in the right eye and a superotemporal defect in the left eye (Fig. 2A). The fundus appearance was unremarkable. MRI of the brain and orbits showed a heterogeneously enhancing mass enlarging the optic chiasm and proximal right optic nerve (Fig. 2B). The patient underwent right frontosphenotemporal craniotomy with lesion resection approximately 8 weeks after symptom onset; both intraoperative appearance (Fig. 2E) and histopathology were consistent with a CM. Postoperatively, the patient noted visual improvement, and when evaluated 13 months after surgery, she was found to have 20/15 visual acuity and normal color vision in each eye. There was a persistent right relative afferent pupillary defect, and moderate right optic disc pallor was seen. Automated perimetry showed improvement in the right eye and complete resolution of the previous defect in the left eye (Fig. 2F). Surveillance MRI demonstrated postoperative changes with no recurrence of the CM (Fig. 2G). FIG. 2. Case 2. A. Automated perimetry before surgery. B. T1W coronal, C. postgadolinium T1W coronal, and D. CT axial at the level of the optic chiasm. No gradient-echo or susceptibility weighted images were obtained. There is an minimally enhanced oval shaped mass with intrinsic T1 hyperintensity some of which has corresponding T2 hypointensity with a suggestion of a rim of T2 hypointensity. CT reveals hyperdensity posteriorly. Findings were compatible with subacute and acute blood with or without calcification. E. Surgical view intraoperatively demonstrating CM mass. F. Automated perimetry 13 months after surgery with improvement. G. T1W coronal after surgery shows removal of the lesion. CM, cavernous malformation. 110 CASE 3 A 33-year-old woman with a history of familial multiple CMs, diagnosed at age 18, reported new-onset severe headache followed by blurred vision. Her visual acuity was 20/20 in each eye with a trace left relative afferent pupillary defect, and she was reported to have a left superior homonymous hemianopia (Figs. 3A, B). MRI of the brain and orbits showed a hemorrhagic lesion of the optic chiasm and right optic tract (Fig. 3C). No intervention was recommended, and about 2 months later, she noted recurrent Kostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution FIG. 3. Case 3. A and B. Automated perimetry at first visit and at last visit. C. T1W coronal, D. postgadolinium T1W coronal fat suppressed, (E) T2W coronal, (F) susceptibility weighted axial image at the level of the chiasm, and (G) susceptibility weighted image of the brain demonstrates a heterogenous mass with foci of T1 hyper and hypo intensity, foci of T2 hypointensity and hyperintensity with a rim of hypointensity and no contrast enhancement. Susceptibility weighted images demonstrate “blooming” or accentuation of the low signal of the optic chiasm mass and numerous regions of susceptibility throughout the brain parenchyma and posterior fossa compatible with multiple old hemorrhages in CMs. Note subtle T1 hyperintensity left inferior frontal lobe with corresponding T2 hyperintensity and rim of low T2 signal compatible with another CM with subacute blood. CM, cavernous malformation. headache and vision loss and was seen in neuroophthalmologic consultation. Visual acuity was 20/400 in the right eye and 20/20 in the left eye with a right relative afferent pupillary defect and reduced color vision in the right eye. Automated perimetry showed a dense left homonymous hemianopia with additional inferotemporal loss in the right eye (Fig. 3B). Both optic discs were pale, right worse than left. Surgery was not recommended by the treating physician because of concern for risk of further visual loss with surgery. The patient was followed with serial examination and MRI; at last visit over 13 years after presentation, her MRI continued to show a lesion within the right optic nerve, chiasm, and right optic tract (Figs. 3D–G) and visual function was unchanged. REVIEW OF REPORTED OPTIC CM CASES We performed a literature search through MEDLINE and NLM PubMed through September 10, 2020, to identify cases of reported CM which resulted in a total of 71 peer-reviewed publications. Of the 68 publications with full-text available, 84 optic CM cases were found. Including the 3 cases in this report, a total of 87 optic CM cases were available. SuppleKostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 mental Digital Content 1 (see Table E1, http://links.lww. com/WNO/A460) provides detailed information available for each case including gender, age, clinical presenting symptoms, CM location, treatment, surgical approach, surgery timing after onset symptoms, follow-up period, baseline and final visual acuity, baseline and final visual field, and outcome. Table 1 summarizes the demographics, presenting symptoms, and CM location of the 87 available cases. Reported optic CMs have a female-to-male preponderance of 10:7, occurring from 1st to 8th decade of life with a mean age of 34 years. Visual loss is the most common symptom (85/87 [98%]), and concurrent headache is often present (44/87 [51%]). Optic chiasm is the most common site of involvement (69/87 [79%]). Of the total 87 optic CM cases, 80 were treated with surgery with outcome available in 77 cases, 7 cases were observed with outcome available in 4 cases, and 1 case was treated steroid. Table 2 summarizes the available outcome information. Most of the surgical treated cases improved (62/77 [81%]). Two of the 4 observed cases improved, and the 1 case treated with steroid worsened. Available baseline and final visual acuity as well as baseline and final visual field are available in Supplemental Digital Content 111 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution TABLE 1. Age, gender, symptoms, and location of reported cases of optic cavernous malformation (details in supplemental table) Age at Presentation Years, Mean ± SD (Range) Gender All (n = 87, 86 with age info) Females (n = 50 [59%])* Males (n = 35, [41%])* Presenting symptoms Visual loss + headache Visual loss Visual loss + nausea Visual loss + headache Visual loss + headache seizure + gait Visual loss + confusion lethargy Visual loss + headache behavior Visual loss + headache speech Headache Dizziness +nausea + 33.7 ± 14.0 (4–78) 35.3 ± 13.3 (4–63) 31.4 ± 15.1 (8–78) Number of cases (total n = 87) 44 (51%) 33 (40%) 2 (2%) 2 (2%) 1 (1%) + 1 (1%) + 1 (1%) + fever + 1 (1%) Optic CM Location Optic Optic Optic Optic chiasm + nerve chiasm nerve chiasm + nerve + tract No. of Cases (Total n = 87) 26 25 12 7 (30%) (28%) (14%) (8%) Optic chiasm + tract Optic chiasm + hypothalamus Optic tract Supraseller Optic chiasm +3rd ventricle 6 3 3 3 1 (7%) (3%) (3%) (3%) (1%) Optic chiasm +3rd ventricle + hypothalamus 1 (1%) 1 (1%) 1 (1%) *n not adding up to n = 87 due to not-available values. CM = cavernous malformation. 1 (see Table E1, http://links.lww.com/WNO/A460), but the numerous unavailable values for many cases prevented valid summary of these visual function measures. DISCUSSION Our 3 cases underscore the importance of recognizing key diagnostic MRI features in suspected optic CMs and the value of expedited surgical excision to improve vision, given optic CM displaces and does not infiltrate neural tissue. The cases had CMs involving the optic chiasm/proximal optic nerve (Cases 1 and 2), and optic chiasm/optic tract (Case 3). Case 1 had sudden visual loss in the right eye, and chiasmal apoplexy was suspected on MRI. Differentiating the lesion from germinoma and optic glioma was difficult. The diagnosis of CM was determined at surgical excision 5 days after onset of symptoms, and significant visual improvement followed. Similarly, Case 2 had acute visual loss and MRI indicated a vascular lesion, and surgical excision of the CM 8 weeks after onset of symptoms resulted in a dramatic improvement of vision. In contrast, Case 3 was diagnosed at age 18 with a history of familial multiple CMs. Vision loss of the right eye from 20/20 to 20/400 occurred within the first 2 months of follow-up. No intervention was recommended, and the visual loss and left homonymous visual field defect persisted with no change of the chiasmal/optic tract lesion. The value of expedited surgical excision to improve vision in optic CMs is supported by a review of 87 reported cases of optic CM (See Supplemental Digital Content 1, Table E1, http://links.lww.com/WNO/A460). Optic CM occurs across gender and nearly all ages with visual loss and headache as the most common presenting symptoms (Table 1). Optic chiasm is the most common site of involvement (79%) and may extend into the optic nerve or optic tract (Table 1). Nearly 95% of reported CM cases were treated with surgery with 81% with improved vision and 1% with worsened vision (Table 2). TABLE 2. Outcome of reported cases of optic cavernous malformation (details in online supplemental table)* Surgery Outcome Improved Stable Worsened No. of Cases (Total n = 77) 62 (81%) 14 (18%) 1 (1%) Observed Outcome Improved Stable Worsened Number of Cases (Total n = 4) 2 (50%) 1 (25%) 1 (25%) *Three cases had surgery with no available outcome; 2 cases were observed with no available outcome; 1 patient was treated with steroid and worsened. 112 Kostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution Although CMs are the most common vascular lesion of the orbit (6), they seldom occur in the optic nerve, chiasm, and tract, accounting for less than 1% of all intracranial CMs (7). Of interest, up to 3 out of 100 people have vascular malformations of the central nervous system (CNS) (8), and CMs represent 10%–20% of CNS vascular malformations (9). Optic CMs are notoriously challenging to suspect and diagnose. A multitude of factors contribute to this low index of suspicion including the low incidence, unusual location, and heterogenous radiographic features. In addition, definitive diagnosis can only be confirmed through surgical intervention, and there may be reluctance in recommending or performing surgery because of concern for risk of visual loss. The most common clinical presentation of optic CMs is likely acute visual loss usually accompanied by headache as a sequela of acute hemorrhage from a chiasmal CM, also referred to as “chiasmal apoplexy” (10), which may or may not be preceded by sentinel bleeds manifested by blurring of vision (11). Optic CMs can also present in a progressive or chronic manner with recurrent episodes of visual disturbance and headache (12). Incidental discovery has also been reported (13). The reported imaging appearance of CMs is variable in their more common locations in the brain. The MRI appearance is more specific. On precontrast CT, CMs commonly appears hyperdense, but mixed hyperdense and isodense lesions have been described (14). Contrast administration may improve the delineation of the lesion with faint enhancement. Specifically, MRI gradient-echo sequences were found to be the most sensitive and specific imaging sequence to diagnose CM (14). Lesions attain a mixed-signal intensity centrally with a hypointense rim; this “popcorn” appearance signifies hemorrhages of different ages (15). Given common MRI protocols for sella and suprasellar lesions do not include small field-of-view thinsection gradient-echo images, careful evaluation of gradientecho images on the brain MRI is important in the assessment of potential optic CMs. A CM should be considered If a popcorn like mass of the optic pathway is seen with a rim of low signal on T2W or T2W gradient-echo imaging. Susceptibility weighted images may accentuate the blood in various stages, given its greater sensitivity for hemorrhage. Careful consideration should also be given to an aneurysm of the circle of Willis when a suprasellar mass is encountered. A CM can look similar to a thrombosed or a partially thrombosed aneurysm on CT and MRI When a chiasmal or perichiasmal mass is encountered that appears to contains blood in various stages, a search of the gradient-echo or susceptibility weighted images of the brain for hemorrhagic lesions with a hemosiderin rim is helpful as in Case 3, given multiple CMs can be encountered in up to a third of patients even in the nonfamilial sporadic form. Optic CM does not infiltrate neural tissue and is resectable in most cases. As seen in Case 1, the initial surgical appearance of optic CM gave the false impression the right optic nerve was unsalvageable (Fig. 1F); yet at the end of resection, a considerable Kostic et al: J Neuro-Ophthalmol 2022; 42: 108-114 portion of the intact optic nerve was clearly visible (Fig. 1G) and can be well appreciated in its remodeled shape on the postoperative MRI a few months later (Fig. 1J). The safety and feasibility of CM resection depend on the recognition of the surgical plane between the lesion and a highly compressed, hemosiderin-laden, and discolored neural tissue. Delicate, sharp development of this cavernoma–gliotic plane with a mixture of microscissors and special microdissectors is essential, given the plane acts as a guide to the surgeon and as a shield protecting intact optic fibers. By staying persistently in the cavernoma–gliotic plane, the surgeon ensures gross total resection, given residual CMs all too often regrow. Any crossing en-passage arterial microvasculature, on its way to the optic structures, must be preserved at all cost to avoid irreversible optic pathway infarction. Taken together, the successful management of optic CMs hinges on the recognition of the MRI features and a high index of suspicion by the neuro-ophthalmologist and neuroradiologist to arrive at the suspected diagnosis, with a timely surgical resection by a neurosurgeon willing to entertain all diagnostic possibilities. Favorable outcomes can thus be achieved. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: M. Kostic and B. L. Lam; b. Acquisition of data: M. Kostic, P. S. Subramanian, S. F. Falcone, S. T. El-Swaify, S. Sur, S. Spasic, N. R. Miller, J. J. Morcos, and B. L. Lam. c. Analysis and interpretation of data: M. Kostic, P. S. Subramanian, S. F. Falcone, S. T. El-Swaify, S. Sur, S. Spasic, N. R. Miller, J. J. Morcos, and B. L. Lam. Category 2: a. Drafting the manuscript: M. Kostic, P. S. Subramanian, S. F. Falcone, J. J. Morcos, and B. L. Lam; b. Revising it for intellectual content: M. Kostic, P. S. Subramanian, S. F. Falcone, S. T. El-Swaify, S. Sur, S. Spasic, N. R. Miller, J. J. Morcos, and B. L. Lam. Category 3: a. Final approval of the completed manuscript: M. Kostic, P. S. Subramanian, S. F. Falcone, S. T. El-Swaify, S. Sur, S. Spasic, N. R. Miller, J. J. Morcos, and B. L. Lam. REFERENCES 1. Deshmukh V, Albuquerque F, Zabramski J, Spetzler RF. Surgical management of cavernous malformations involving the cranial nerves. Neurosurgery. 2003;53:352–357. 2. Matias-Guiu X, Alejo M, Sole T, Ferrer I, Noboa R, Bartumeus F. Cavernous angiomas of the cranial nerves. J Neurosurg. 1990;73:620–622. 3. Del Curling O Jr, Kelly D Jr, Elster A, Craven TE. An analysis of the natural history of cavernous angiomas. J Neurosurg. 1991;75:702–708. 4. Otten P, Pizzolato G, Rilliet B, Berton J. 131 Cases of cavernous angioma (cavernomas) of the CNS, discovered by retrospective analysis of 24,535 autopsies. Neurochirurgie. 1989;35:82–83. 5. Robinson J, Awad I, Little J. Natural history of the cavernous angioma. J Neurosurg. 1991;75:709–714. 6. Shields JA, Bakewell B, Augsburger JJ, Flanagan JC. Classification and incidence of space-occupying lesions of the orbit. A survey of 645 biopsies. Archiv Ophthalmol. 1984;102:1606–1611. 7. Hassler W, Zentner J, Wilhelm H. Cavernous angiomas of the anterior visual pathways. J Clin Neuroophthalmol. 1989;9:160–164. 8. Al-Shahi R, Bhattacharya JJ, Currie DG, Papanastassiou V, Ritchie V, Roberts RC, Sellar R, Warlow Ch. Prospective, population-based detection of intracranial vascular 113 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Original Contribution malformations in adults: the Scottish Intracranial Vascular Malformation Study (SIVMS). Stroke. 2003;34:1163– 1169. 9. Moriarity JL, Clatterbuck RE, Rigamonti D. The natural history of cavernous malformations. Neurosurg Clin N Am. 1999;10:411–417. 10. Maitland CG, Abiko S, Hoyt WF, Wilson CB, Okamura T. Chiasmal apoplexy. Report of four cases. J Neurosurg. 1982;56:118–122. 11. Arrué P, Thorn-Kany M, Vally P, Lacroix F, Delisle MB, Lagarrigue J, Manelfe C. Cavernous hemangioma of the intracranial optic pathways: CT and MRI. J Comput Assist Tomogr. 1999;23:357–361. 114 12. Cerase A, Franceschini R, Battistini S, Maria Vallone I, Penco S, Venturi C. Cavernous malformation of the optic nerve mimicking optic neuritis. J Neuroophthalmol. 2010;30:162–131. 13. Trentadue M, Mucelli RP, Piovan E, Pizzini FB. Incidental optochiasmatic cavernoma: case report of an unusual finding on 3 Tesla MRI. Neuroradiol J. 2016;29:289–294. 14. Rigamonti D, Drayer BP, Johnson PC, Hadley MN, Zabramski J, Spetzler RF. The MRI appearance of cavernous malformations (angiomas). J Neurosurg. 1987;67:518–524. 15. Liu JK, Lu Y, Raslan AM, Gultekin SH, Delashaw JB Jr. Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature. Neurosurg Focus. 2010;29:E17. 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