[A non-healing ulcer between the toes]

A 60-year-old man presented with a non-healing interdigital ulcer on the right foot. Various treatment regimens had no effect. Three months later, histopathological examination of a biopsy showed an acrolentiginous amelanotic melanoma. Partial foot amputation followed, but metastases were diagnosed several months later. If no improvement occurs in a benign-looking acral lesion, doctors should closely observe the lesion and consider biopsy.