A case of choroidal melanocytoma treated by transscleral resection: A clinicopathological study.

Choroidal melanocytoma is a rare benign melanocytic tumor. We report a case of choroidal melanocytoma that was definitively diagnosed by histopathological findings after local resection. A 71-year-old female complained of blurred vision in her left eye. Her best-corrected visual acuity (BCVA) was 1.0. A dark-brown elevated lesion, measuring 5 papilla-diameter was found in the periphery of the fundus in her left eye. The mass showed hyperfluorescence on fluorescein angiography, early hypofluorescence and late hyperfluorescence on indocyanine green angiography. B-mode echography indicated the mass was originated from the choroid. Orbital magnetic resonance imaging showed isointense signal intensity on T1-weighted images (WI) and hypointense signal intensity on T2-WI, and poor Gadolinium enhancement on T1WI. The tumor was suspected to be melanocytoma, but it was difficult to differentiate from malignant melanoma. Transscleral tumor resection combined with 25-gauge vitrectomy was performed. Histopathological examinations led to the diagnosis of choroidal melanocytoma. Two years after local resection, her BCVA was 1.0 with no tumor recurrence. Local resection was useful as a diagnostic treatment for choroidal tumors confined to the periphery of the fundus that were difficult to clinically differentiate from malignant melanoma.