Atypical ulcer arising on stasis dermatitis: achromic melanoma

Due to venous insufficiency, a vascular ulcer frequently occurs with the progression of stasis dermatitis. Achromic melanoma, a rare form of pigmentless melanoma frequently located on the sole of the foot, is often and easily confused with a typical wound. Diagnosis of ulcerated achromic melanoma is thus often delayed and associated with a poor prognosis.

The authors report a very rare case of malignant melanoma in a 70-year-old female with stasis dermatitis. The painless ulcer was present for 1 year before the first visit. Upon clinical examination, a 2-cm diameter hypergranulating ulcer with irregular and pigmented borders was present. Dermoscopy revealed the presence of red globules, a gray-to-blue veil, irregular vessels, and the remains of a pigmented ridge pattern. Histological analysis showed infiltration of atypical melanocytes in the dermis, 2 mitoses, and ulceration. Diagnosis of melanoma was confirmed by positive MART-1 immunochemistry. After removal of the melanoma, the area was covered with an autologous skin graft excised from the inner thigh. In accordance with the guidelines, sentinel lymph node biopsy was performed, and the result was negative for lymph node involvement. A comprehensive clinical dermoscopic evaluation led to the correct diagnosis.

The current case highlights the importance of evaluating a chronic, atypical, nonhealing ulcer clinically and dermoscopically as well as through a biopsy procedure.