A rare case of unilateral axillary supernumerary breast

Polymastia or supernumerary breast is an anomaly of the embryonic development of the mammary gland resulting in ectopic breast tissue. We report an exceptional case of a unilateral axillary supernumerary breast in a 71-year-old patient which became enlarged after menopause. The diagnosis was confirmed on anatomopathological study which revealed no sign of malignancy otherwise. In our case, it was a proliferation of glandular tissue, without areola or nipple, rarely reported in the literature, and corresponding to Kajava class IV. The patient underwent surgical treatment in order to resolve the problem of aesthetic discomfort and to limit the risk of malignant transformation.