Mammary hamartoma with brown adipose tissue.

This report documents a rare variant of mammary hamartoma with presence of lobules of brown adipose tissue. The lesion was discovered in a control mammogram performed in a 42-year-old woman 15 months after hormonal substitute therapy for radical hysterectomy with bilateral salpingo-oophorectomy. Complete excision is the adequate therapy. The presence of brown fat in the hamartoma should be considered in the differential diagnosis of the exceptional hibernoma of the breast and other tumors composed of large cells with granular or multilocular cytoplasm, such as lipoblastoma, sebaceous adenoma, granular cell tumor and histiocytoid or lipid rich carcinomas.