A pink enlarging plaque on the plantar foot: amelanotic acral lentiginous melanoma.

Acral lentiginous melanomas account for less than 5% of all melanomas, whereas amelanotic melanomas account for around 2-8% of all melanomas. Amelanotic acral lentiginous melanomas are even less common and can often be mistaken for other clinical entities, including pyogenic granulomas, non-melanoma skin cancers, and warts. We describe a man in his 50s with a twenty-year history of a skin-colored plaque on the right plantar foot; after enlargement and failure of wart treatment, a shave biopsy revealed an amelanotic melanoma. A subsequent wide local excision and sentinel lymph node biopsy revealed melanoma in 4 lymph nodes and the patient underwent an abbreviated course of interferon-alpha therapy. The patient remained stable until 2 ? years after diagnosis, at which time he presented with in-transit metastases on the foot and right thigh; he has since been stable on nivolumab. This case represents the challenge of diagnosing amelanotic melanomas on acral surfaces and highlights the importance of considering a skin biopsy for diagnosis of any changing, atypical amelanotic lesions on the feet or hands.