Intra-articular melanoma metastases are rare. We present a case of a 65-year-old woman with metastatic melanoma in the right ankle joint. 18F-FDG PET/CT was performed from the vertex to the toes, which demonstrated FDG-avid inguinal lymphadenopathy and an intensely FDG-avid soft tissue mass adjacent to the neck of the talus within the right ankle joint. The intra-articular mass was subsequently resected and histologically confirmed as metastatic melanoma. This case emphasizes the value of the contemporaneous CT in these studies for accurate anatomical localization in diagnostically challenging clinical scenarios.