RESUMEN
Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing mesenchymal neoplasm of the dermis and subcutaneous tissues that has a low-to intermediate-grade malignancy. DFSP commonly involves the trunk and extremities, and very rarely the breast skin, mimicking a primary breast neoplasm with few reported cases in the literature. We report a 35-year old female patient who was referred to the Royal Hospital, Muscat, Oman in 2017, with a two-year history of a slow growing left breast lump. Assessment of the breasts with mammography revealed a lobulated lesion in the left-upper-inner quadrant with neither microcalcification nor architectural distortion, mimicking a benign lesion. However, on ultrasound, the lesion had suspicious features with increased vascularity and hence, it was categorised as breast imaging reporting and data system (BIRAD) IV. The patient underwent left breast wide local excision and the histopathological diagnosis was dermatofibrosarcoma protuberans.