[Nodular mucinosis of the breast]

Nodular mucinosis of the breast is a rare entity of uncertain histogenesis and with benign behavior. It usually presents as an asymptomatic tumor around the nipple or areola and located in the dermis or subcutaneous cellular tissue. We present a case of typical nodular mucinosis. Histologically it is defined as being composed of irregular lakes of mucin negative with PAS but positive with colloidal iron and alcian blue. Mucin is accompanied by fibrous stroma with a scarce component of fusiform cells. Some authors suggest a possible myofibroblastic origin. However, molecular studies of nodular mucinosis have not been performed. The differential diagnosis must be made mainly with benign and malignant mammary lesions of mucinous stroma. In the literature, 13 cases of nodular mucinosis are described.