Cystoid macular edema as the initial manifestation of choroidal melanoma.

Uveal melanomas are a common clinical entity that initially present in a variety of ways. Cystoid macular edema is caused by many conditions, but it is rarely associated with uveal melanoma. We report two cases of patients that presented with visually significant cystoid macular edema that was later found to be secondary to choroidal melanoma. We describe the patients' course and treatment and provide a mechanism for the potential cause of edema in patients with uveal melanoma.

Introduction

Cystoid macular edema (CME) is a recognized manifestation of several ocular disorders including diabetic or hypertensive retinopathy, retinal vein obstruction, chronic inflammatory conditions, and post cataract extraction.[1] Intraocular tumors, such as retinal hemangioblastoma and vasoproliferative tumors, can occasionally produce CME.[2] In contrast, CME is notably rare with uveal melanoma. In this report, we describe two patients who initially manifested with visually symptomatic CME, later found to be secondary to choroidal melanoma.

Case Reports

Case 1

A 52-year-old healthy man presented with decreased vision in the left eye (OS) for more than two months. Visual acuity was 20/20 right eye (OD) and 20/60 OS. Fundus examination disclosed CME OS, confirmed with fluorescein angiography and optical coherence tomography (OCT) at 733 microns thickness. In addition, there was a choroidal melanoma, located at the superotemporal equator, with basal dimension of 13 mm. [Figure 1]. Extramacular overlying serous retinal detachment and chronic retinal pigment epithelial (RPE) atrophy was noted. There was retinal invasion over the tumor apex and a prominent draining retinal vein. The lesion displayed acoustic hollowness and measured 4 mm thickness on ultrasonography.

Figure 1

A 52-year-old man with cystoid macular edema on fluorescein angiography (a) and optical coherence tomography (b). Note the superotemporal equatorial choroidal melanoma with retinal invasion and prominent retinal draining vein (c)

The melanoma was treated with plaque radiotherapy (8 000 cGy apical dose) combined with three sessions of transpupillary thermotherapy. Additional intravitreal bevacizumab was delivered to assist in resolution of CME. At ten months, there was an improvement in the visual acuity to 20/40 OS as a result of reduction in CME to 329 microns. At 30 months, stable tumor regression to 1.2 mm was documented, but visual acuity decreased to 20/100 from radiation maculopathy, with foveal thickness of 609 microns.

Case 2

A 13-year-old healthy female presented with complaints of blurred peripheral vision and shadowing in the right eye. Visual acuity was 20/20 OD and 20/40 OS. Fundus examination disclosed CME OS, confirmed with fluorescein angiography and OCT at 442 microns thickness. In addition, there was an amelanotic choroidal melanoma with basal dimension of 12 mm. B-scan ultrasonography revealed a 3.1-mm thick, acoustically hollow mass [Figure 2]. There was no retinal invasion, but overlying RPE atrophy was found. The melanoma was treated with two sessions of photodynamic therapy plus additional intravitreal bevacizumab for CME. At 16 months, tumor regression to 2.5 mm was documented and visual acuity was stable at 20/40 OD, with reduction in CME to 392 microns.

Figure 2

A 13-year-old female with cystoid macular edema confirmed on fluorescein angiography (a) and optical coherence tomography (b) and a temporal peripheral choroidal melanoma with retinal pigment epithelial atrophy (c)

Discussion

CME secondary to choroidal melanoma could develop based on several mechanisms including chronic retinal degeneration overlying subfoveal melanoma, chronic subfoveal retinal detachment with later intraretinal edema and CME, inflammatory reaction to necrotic tumor, or remotely from intravitreal biochemical tumor-related factors. Boyd et al. found elevated vascular endothelial growth factors (VEGF) in the vitreous in eyes with choroidal melanoma.[3] They measured VEGF-A levels up to 21.6 ng/ml in melanoma-containing eyes, compared to values below 0.96 ng/ml in normal eyes. This alone could contribute to CME. However, despite elevated VEGF, CME is rarely observed.

A PubMed search for “macular edema,” “cystoid macular edema,” “choroid,” “melanoma,” and “eye” yielded only one previously published case of choroidal melanoma with CME, reported by Brownstein and associated in 1978.[4] In that report, a 32-year-old man with equatorial extramacular choroidal melanoma and minimal adjacent subretinal fluid manifested reduced visual acuity from CME. Histopathology of the enucleated eye disclosed CME and retinal perivasculitis overlying and remote from the choroidal melanoma. The authors emphasized the rarity of this finding and speculated that “although the simultaneous occurrence of CME and uveal melanoma… may have been coincidental, it is more likely that these findings were related.” They referred to a similar single case previously published in 1972.[5]

We speculate that CME developed in case #1 related to intraretinal invasion by tumor that could have caused retinovitreal disruption and biochemical instability, leading ultimately to CME. In case #2, the chronic overlying RPE alterations and localized subretinal fluid could have lead to direct CME or remote CME from vitreoretinal biochemical factors.

In summary, we describe two cases of uveal melanoma that displayed CME. Despite published documentation of elevated aqueous and vitreous VEGF levels in uveal melanoma, CME rarely develops.