We report two patients who developed a second distinct choroidal melanoma in the same eye following successful regression of their first choroidal melanoma after iodine-125 plaque brachytherapy. Neither patient demonstrated ocular melanocytosis, local tumor recurrence, or vitreous seeding. One patient had the second tumor arising from a previously documented choroidal nevus, and after undergoing enucleation, there was no detectable connection between the tumors on histopathologic examination. Germline BAP1 mutation was absent in both cases. Multifocal primary uveal melanoma is a rare entity in which the second tumor may occur either de novo or from a malignant transformation of a choroidal nevus. Known risk factors include ocular melanocytosis or germline BAP1 mutation. Additional underlying mechanisms have yet to be elucidated.
Keywords: Choroidal nevus malignant transformation; Germline BAP1 mutation; Iodine-125 plaque brachytherapy; Multifocal uveal melanoma.