Amelanotic malignant melanoma in an acral location

We present the case of a 74-year-old white female admitted to the Department of Dermatology because of a tumor in the IV-V interdigital area of her right foot. A crimson, dome-shaped tumor with a granular, spongy surface (diameter 4 cm) had developed over a period of about 3 months. The biopsy, stained with H and E, revealed an anaplastic malignant tumor. Additional immunochemical staining with Melan A allowed us to make the final diagnosis: amelanotic malignant melanoma (MM). The melanoma was removed by amputation of digits IV and V, with partial removal of the metatarsal bones (Clark degree 5, Breslow thickness 9 mm). Sentinel node biopsy was done using Tc99; it revealed no neoplastic alteration. The patient is still under oncological observation.