Presumed Melanoma of Unknown Primary Origin Metastatic to the Choroid Mimics Primary Uveal Melanoma.

We describe the case of a 69-year-old woman who presented with a decline in vision in the left eye and was found to have a choroidal lesion with clinical and echographic features concerning for primary uveal melanoma. Systemic imaging identified numerous metastases to the liver, kidneys, paratracheal lymph nodes, lung, and brain. The hepatic lesion was biopsied, and genetic analysis identified a Val600Glu (c.1799T>A) mutation, consistent with a cutaneous primary malignancy, although no primary tumor was identified. This case highlights that metastasis to the choroid is a rare presentation of nonuveal melanoma that can mimic primary uveal melanoma. Genetic analysis of tumor tissue can identify the origin of the melanoma and guide treatment options. Systemic imaging should be performed prior to intervention for choroidal neoplasms.