Unilateral Multifocal Choroidal Melanoma with Underlying Isolated Choroidal Melanocytosis

Abstract

Isolated choroidal melanocytosis is a rare condition that appears to be a limited form of ocular melanocytosis. Ocular melanocytosis has been known to be associated with an increased risk of uveal melanoma, and more recently, a similar association has been suggested for isolated choroidal melanocytosis. We describe 3 cases of patients who developed unilateral, multifocal uveal melanoma in the setting of underlying isolated choroidal melanocytosis. All patients developed either two distinct tumors at presentation or a new discrete choroidal melanoma arising from the choroidal melanocytosis over 1 year following treatment of the original tumor by plaque brachytherapy. These cases provide additional evidence of the association between isolated choroidal melanocytosis and uveal melanoma and suggest increased risk of multifocal melanoma in patients with this condition.

Keywords: Choroidal melanoma; Isolated choroidal melanocytosis; Multifocal choroidal melanoma; Posterior uveal melanoma.

Fig. 1

a Widefield fundus photograph of the left eye demonstrating a darkly pigmented, nodular, elevated choroidal tumor in the temporal periphery with an underlying area of isolated flat hypermelanotic choroid consistent with choroidal melanocytosis. b Fundus autofluorescence shows diffuse overlying lipofuscin pigment. c Widefield fundus photograph of the left eye 22 months following plaque brachytherapy showing regression of the temporal lesion with a new elevated, pigmented choroidal tumor in the superior periphery arising from the choroidal melanocytosis. d Fundus autofluorescence shows prominent lipofuscin pigment along the posterior margin of the superior lesion.

Fig. 2

a Histopathologic examination of the previously treated temporal melanoma demonstrating spindle-cell morphology (H&E, OM ×400). b Newly occurring superior melanoma demonstrating mixed (spindle and epithelioid)-cell morphology (H&E, OM. ×400). c The choroid separating the 2 foci of melanoma reveals increased benign dendritic melanocytes with plump densely pigmented polyhedral melanocytes and pigment-laden macrophages, typical for choroidal melanocytosis (H&E, OM. ×400). H&E, hematoxylin and eosin; OM, original magnification.

Fig. 3

a Widefield fundus photograph of the right eye demonstrating a darkly pigmented choroidal tumor with prominent overlying lipofuscin and a large associated area of choroidal melanocytosis superotemporally. b Widefield fundus photograph 14 months following plaque brachytherapy showing regression of the macular lesion with a new elevated, pigmented melanoma in the superotemporal periphery arising from the choroidal melanocytosis (white arrow).