RETINAL ONCOLOGY CASE REPORTS IN OCULAR ONCOLOGY SECTION EDITORS: CAROL L. SHIELDS, MD; AND SARA LALLY, MD Visual Field Defects From Optic Disc Melanocytoma

BY EMIL ANTHONY T. SAY, MD; NEELEMA SINHA, MD; AND CAROL L. SHIELDS, MD

ptic disc melanocytoma is a darkly pigment- CASE DESCRIPTION ed mass of the optic disc characterized A 33 year-old white man perceived an inferior visual histopathologically by Zimmerman and field defect in his right for 1 month. Visual acuity O Garron1 in 1962 as a uniform accumulation was 20/20 in both , and intraocular pressures were of heavily pigmented cells with abundant cytoplasm, 19 mm Hg in both eyes. External and anterior segment small nuclei, and inconspicuous nucleoli, all of which are examination was unremarkable for both eyes. The benign cellular characteristics resembling ocular patient had brown irides without ocular melanocytosis. melanosis. In 2004, Shields and colleagues2 described the examination of the left eye was unremarkable, clinical features in a large cohort of 115 patients and but the right eye showed a pigmented lesion occupying related, that melanocytoma, although benign, has the the superior half of the optic disc from 10 to 2:30 o’clock, capacity to cause significant visual morbidity. They with extension into the juxtapapillary superotem- reported that at 10 and 20 years, respectively 18% and porally and lacking a choroidal component (Figure 1). 33% will lose two or more lines of vision by Kaplan-Meier Optic disc edema was present but retinal vessels were estimates.2 We report a case of optic disc melanocytoma not dilated or tortuous. Both fluorescein and indocya- with notable visual field loss. nine green angiography revealed hypofluorescence corre-

Figure 2. Fluorescein (A,B) and indocyanine green (C,D) Figure 1. Fundus photo showing a superiorly located pig- angiograms showing hypofluorescence of the lesion in all mented optic disc melanocytoma with extension into the jux- phases. There was also mild leakage seen on fluorescein tapapillary retina that was more prominent superotemporal- angiogram along the inferotemporal optic disc correlating ly (white arrows). A choroidal component was absent. Note with the moderate disc edema. This was not visualized on the moderate disc edema. indocyanine green angiography.

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When anatomic findings and functional tests do not correlate, other etiologies should be sought.

and homonymous.3 It is important to localize the defect as each site could portend a different prognosis.3-5 Visual field defects can be detected in up to 90% of patients with optic disc melanocytoma.2,6-8 In a series of 115 patients with optic disc melanocytoma studied for visual field defects, the most commonly reported visual field abnormality was enlargement of Mariotte’s blind spot, found in 32% of patients.2 The size of the blind spot corre- sponds to the extension of the lesion beyond the boundary of the optic disc.9 This extension causes a shadowing effect Figure 3. Correlation of the predominantly superotemporal on the peripapillary retina and subsequent blind spot extension of the optic disc melanocytoma to the adjacent enlargement.9 Osher and colleagues6 highlighted this phe- retina (A,C) and the inferonasal paracentral (B,D). nomenon by demonstrating that melanocytomas confined The clinical features and visual field defect remained stable within the optic disc displayed normal visual fields. from his initial visit (A,B) and 14 years later (C,D). In addition to enlargement of the blind spot, patients can also display an arcuate defect, quadrantal defect, sponding to the lesion, with some mild leakage on fluo- nasal step, or paracentral scotoma representing impaired rescein angiogram along the inferotemporal optic disc axonal flow secondary to mechanical compression that correlated with disc edema (Figure 2). Visual field directly on the nerve fiber bundles or microcirculation.6 examination showed an inferonasal paracentral scotoma Nerve fiber bundle defects should correlate to the loca- on the pattern deviation plot corresponding to the pre- tion of the lesion. Our patient had extension beyond the dominantly superotemporal juxtapapillary extension of superior margin of the disc that was mostly superotem- the optic disc tumor (Figure 3). Magnetic resonance poral, resulting in an inferonasal paracentral scotoma. imaging (MRI) of the brain and orbits revealed no deep Over 14 years, there was no demonstrable growth of the abnormality. These findings were consistent lesion, and the visual field examination remained stable. with the diagnosis of optic disc melanocytoma. The Furthermore, when both superior and inferior nerve fiber patient was monitored yearly. layers are involved, patients may have double arcuate After 14 years of follow up, visual acuity remained sta- defects leading to constriction of the visual field and a ble at 20/20 in both eyes with no significant change in residual central island.7 When extensive nerve fiber appearance. The visual field defect remained stable involvement occurs, patients may also have significant (Figure 3). retinal cell loss and a concomitant afferent pupillary defect, as seen in 9% of cases.2 DISCUSSION When anatomic findings and functional tests do not Visual field defects reflect abnormalities in the visual correlate, other etiologies should be sought. For example, pathway.3 Much as a neurologist will localize an abnormal- in a case report by Rai and co-workers,10 a patient present- ity to the brain, spinal cord, or the peripheral nerve by cor- ed with optic disc melanocytoma, but visual fields showed relation with clinical findings, an ophthalmologist can rec- an inferior arcuate defect that correlated with thinning of ognize and localize a visual field defect to either the pre- the superior neuroretinal rim more consistent with glauco- chiasmal, chiasmal, or post-chiasmal visual pathway. Pre- ma than melanocytoma. In Zimmerman and Garron’s1 chiasmal defects are unilateral and ipsilateral, chiasmal original series of 28 eyes with optic disc melanocytoma, defects will almost always be bitemporal, while post-chias- glaucomatous visual field defects were found in three mal involvement cause visual defects that are contralateral cases, which further highlights this point. These cases

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The world’s emphasize the importance of meticulous examination of the neuroretinal rim in both the involved and fellow eye and correlation with the visual field results.10 Intracranial #1 meningioma can also be associated with optic disc melanocytoma and should be suspected if visual field online source for defects respecting the vertical midline are found.4,5 In summary, optic disc melanocytoma is a benign pig- ophthalmic videos mented lesion that can lead to a myriad of visual field dis- turbances. Correlation of clinical and visual field findings is of utmost importance to effectively rule out other etiolo- gies and estimate visual prognosis. Patients with optic disc melanocytoma should be monitored annually for ocular

.net findings and particularly for transformation of the benign tumor into melanoma, a feature found in 2% of cases.2 ■

Support provided by the Eye Tumor Research Foundation, Philadelphia, PA (CLS). The authors have no financial interests to disclose. Emil Anthony T. Say, MD, is a fellow with the Ocular Oncology Service, Wills Eye Institute, Thomas Jefferson University in Philadelphia. He can be reached via e-mail at [email protected]. Thousands of videos Neelema Sinha, MD, is a student of Drexel b with audio tracks University College of Medicine. She can be reached via e-mail • at [email protected]. High-Definition Carol L. Shields, MD, is the Co-Director of the Ocular Oncology Service, Wills Eye video Hospital, Thomas Jefferson University. • Dr. Shields is a member of the Retina Today Editorial Board. She may be reached at Links to articles carol.shields@shieldsoncology. com; phone: +1 215 928 3105; fax: +1 215 928 1140. tube • Sara E. Lally, MD, is with the Ocular Oncology Service and is a Clinical Instructor at Thomas Jefferson University.

1. Zimmerman LE, Garron LK. Melanocytoma of the optic disk. Int Ophthalmol Clin. 1962;2:431-440. 2. Shields JA, Demirci H, Mashayekhi A, Shields CL. Melanocytoma of optic disc in 115 cases: watch + listen + learn The 2004 Samuel Johnson Memorial Lecture, part 1. Ophthalmology 2004;111:1739-1746. 3. Lee AG, Brazis PW. Visual field defects. In: Lee AG, Brazis PW. Clinical Pathways in Neuro- Ophthalmology: An Evidence-Based Approach. New York, NY: Thieme; 2003: 189-214. www.eyetube.net 4. Shinoda K, Hayasaka S, Nagaki Y, Kadoi C, Kurimoto M, Okada E. Melanocytoma of the left optic nerve head and right retrobulbar compressed by a tuberculum sellae meningioma. Ophthalmologica. 200;214:161-163. 5. Walsh TJ, Packer S. Bilateral melanocytoma of the optic nerve associated with intracranial Find us on meningioma. Ann Ophthalmol. 1971;3:885-888. 6. Osher RH, Shields JA, Layman PR. Pupillary and visual field evaluation in patients with melanocytoma of the optic disc. Arch Ophthalmol.1979;97:1096-1099. 7. Zografos L, Othenin-Girard CB, Desjardins L, Schalenbourg A, Chamot L, Uffer S. Melanocytomas of the optic disk. Am J Ophthalmol. 2004;138:964-969. & 8. Usui T, Shirakashi M, Kurosawa A, Abe H, Iwata K. Visual disturbance in patients with melanocytoma of the optic disk. Ophthalmologica. 1990;201:92-98. 9. Shields JA, Demirci H, Mashayekhi A, Eagle RC, Shields CL. Melanocytoma of the optic disk: a review. Surv Ophthalmol. 2006;51:93-104. eye 10. Rai S, Medeiros FA, Levi L, Weinreb RN. Optic disc melanocytoma and . Semin Ophthalmol. 2007;22:147-150.