Breast Imaging Findings in Dermatofibrosarcoma Protuberans: A Case Report and Review of Literature.

Dermatofibrosarcoma protuberans (DFSP) is a rare, indolent, cutaneous sarcoma originating in the dermis, and although nearly half of cases occur on the trunk, DFSP of the breast is exceedingly rare, and imaging findings may resemble primary breast neoplasms. In this case report, a previously healthy, middle-aged female patient presented to the clinic with the complaint of abnormal growth in her left breast, which had been gradually increasing in size over the course of four years. Imaging of the left breast demonstrated a large, exophytic, partially intradermal mass with internal vascularity, raising concern for a primary breast neoplasm. Ultrasound-guided core needle biopsy revealed a diagnosis of DFSP. She underwent successful left skin- and nipple-sparing mastectomy with complete resection of the mass with negative margins confirmed on surgical pathology. Recognizing key features of DFSP on conventional breast imaging modalities, such as mammography and ultrasound, can be helpful in differentiating DFSP from primary breast neoplasms, but imaging findings alone may be nonspecific and biopsy is necessary for a definitive diagnosis. On mammography, DFSP typically presents as an exophytic, gently lobulated, non-calcified, and circumscribed mass. On sonographic examination, DFSP appears as a circumscribed, parallel-oriented mass that is hypoechoic relative to the surrounding fat, with intervening echogenic bands, posterior acoustic enhancement, and intralesional hypervascularity visualized on color Doppler. Although DFSP is slow-growing with a low incidence of metastatic disease, it has a high local recurrence rate and aggressive local resection is necessary to minimize the chance of recurrence.