[Breast carcinoma with melanocytic differentiation].

Azzopardi and Eusebi were the first to describe pigmented breast cancers in 1977. They postulated that the mammary cancer might become colonized by melanocytes at the expense of the epidermis, which was focally depleted of melanocytes, and that it occurred in most cases of breast cancers in which tumor cells reached the dermal-epidermal interface. Other authors suggested melanocytic differentiation of tumor cells. In this paper a case of a patient with ductal invasive breast cancer with partial melanocytic differentiation was presented, documented by HMB-45 and melan-A reactivity of tumor cells. Tumor was positive with antibodies for estrogen and progesterone receptors, pancytokeratin, negative with antibodies for S-100 protein and vimentin. Masson-Fontana reaction was negative. It was concluded that pigmented tumors should be differentiated from tumors with partial melanocytic differentiation, and that clinical significance of melanocytic differentiation should be analysed on larger number of cases.