Pigmented mammary Paget disease mimicking cutaneous melanoma

Mammary Paget Disease With Melanocytic Proliferation Mimicking Malignant Melanoma in situ: A Case Report

Several cases of pigmented mammary Paget’s disease (PMPD) mimicking cutaneous malignant melanoma have been reported. In these cases, the tumor cells are colonized by melanocytes, particularly with the presence of a population of melanocytes staining for HMB-45 and S100. Here, we report a case of mammary Paget disease (MPD) which was misdiagnosed as melanoma in situ due to the interpretation of the staining of melanocytic markers S-100, Melan-A, and HMB-45. The tumor cells strongly expressed CK7 and GATA3, and a dual-labeling showed negative PHH3 labeling for the melanocytes. Pathologists need to be aware of the caveat of colonization of melanocytes in Paget disease.

Pigmentary mammary Paget disease: Clinical, dermoscopical and histological challenge

A very rare variant of mammary Paget disease (MPD) is the pigmented MPD, first described in 1956. It is very difficult to distinguish this variant from melanoma both clinically and dermoscopically. The diagnosis is confirmed by histopathology and immunohistochemistry. Correct diagnosis is crucial for surgical treatment, which is different for these two diseases. We report the case of a 92-year-old woman, who presented an asymptomatic pigmented lesion of the right nipple and areola. The lesion was arisen for about 6 months and was suspected for melanoma because of clinical and dersmoscopic characteristics. Incisional biopsy revealed tumor cells, that proliferate in the major mammary ducts, and tumor cells in the overlying epidermis of the nipple, thus diagnosing pigmented mammary Paget disease. The patient underwent radical mastectomy.