Dermatofibrosarcoma Protuberans: A Rare Malignancy of the Breast.

Dermatofibrosarcoma protuberans (DFSP) of the breast is a rare skin cancer with only a few cases reported in the literature. It corresponds to approximately 1% of all soft tissue sarcomas and to less than 0.1% of all malignancies with annual incidence of 0.8-4.5 cases per million. DFSP usually affects young and middle-aged adults and it can affect any site, but most commonly the trunk and extremities. This tumor arises from the deep dermis and subcutaneous tissues and is usually locally aggressive, but rarely metastasizes. Surgery including wide local excision with free margins remains the main modality of treatment. We report a case in a 28-year-old Omani woman who presented with a right breast lump to a local secondary hospital. She was offered excision biopsy of the lump and the histology came as DFSP with involved margins. The patient was then referred to the Breast Unit at the Royal Hospital where she was reviewed by multidisciplinary team including breast surgeons, oncologists, radiation oncologists, pathologists, and breast radiologists. Her laboratory and radiological investigations did not show any signs of distal metastasis and breast ultrasound did not reveal any residual breast lesions. We performed a wide re-excision of the previous surgical scar with the underlying breast tissues down to the level of the pectoral fascia followed by treatment with radiotherapy. The final histology report showed the presence of a 4×5mm residual tumor, and all resection margins were tumor-free. At six months follow-up, she had no signs of local recurrence. We publish this case report because of its rarity.