Dermatofibrosarcoma of the breast: A case report

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade fibroblastic mesenchymal tumor that develops in the dermal and hypodermal layers of the skin. DFSP arises typically on trunk and proximal limbs followed by the extremities. Intra-breast DFSP is even more uncommon, with only a handful of cases described in the literature.

We report the case of a 40-year-old woman who underwent her first breast screening. It revealed a 18mm mass in the lower outer quadrant of the right breast categorized as Breast-Imaging-Reporting and Data System (BIRAD) IV. A core-needle biopsy was performed and revealed a DFSP. We performed a monobloc cutaneous-glandular excision in the form of a T-shaped oncoplasty with a superior pedicle. Clear margins were obtained.

Intra-breast localizations are rare. Only a handful of cases have been reported in the literature, and only a few of these are truly intramammary, where the tumor arises in the subcutaneous tissue, complicating the clinical differential diagnosis with other benign breast tumors. Imaging may suggest a benign breast tumor, MRI may be helpful in the diagnosis. The overall recurrence rate is 7.3% and is directly related to the surgical margins achieved. Given the dermal origin of this tumor and its "tentacular" invasion, resection of the skin seems to be indicated and should be taken into account in the surgical procedure.

This case illustrates that dermatofibrosarcoma is not always an obvious diagnosis, particularly in its intramammary forms. A wide skin resection must be performed to obtain clear margins.