Acral melanoma with satellitosis, disguised as a longstanding diabetic ulcer: a great mimicry

Acral lentiginous melanoma affects the palms, soles, and nail apparatus. Around 3-15% of all cutaneous melanomas are located on the foot and have a poorer prognosis than melanoma elsewhere. Possible reasons for this prognostic difference may be omitting this area during routine skin check by both the patient and the physicians, in addition to misdiagnosis of melanoma as other benign skin lesions. We describe here an elderly female patient treated for a non-healing foot ulcer interpreted as a diabetic ulcer, which after 2 years was diagnosed as acral melanoma with satellitosis. Histopathological examination of the amputated distal phalanx revealed an advanced stage melanoma with 1·2 cm Breslow thickness and of Clark level 5. Dermoscopy of the bluish papulonodules scattered on the dorsal foot showed characteristic findings described for metastasis of skin melanoma. This case underlines the importance of considering skin malignancies in case of chronic, non-healing ulcers in diabetic patients. Furthermore, we point out the critical significance of skin examination as a whole, and dermoscopy being an important tool in the diagnosis of melanoma and/or cutaneous melanoma metastasis.