Introduction: Dermatofibrosarcoma is a sarcoma of intermediate degree of malignancy with strong local aggressiveness with a low but real metastatic potential. Its breast location is very rare. Observation: It was a 40-year-old woman who has never been pregnant who was followed for a retro-areolar tumor of the ulcerated left breast that had been evolving for more than eight weeks. A mammary cytopract was done which was in favor of a phyllode tumor. We performed a large surgical excision on the patient and the histology of the operative specimen was in favor of a dermatofibrosarcoma of Darier and Ferrand with healthy resection margins. Discussion: The mammary location of Darier and Ferrand syndrome is rare. With early diagnosis an infectious and hemorrhagic complication can be avoided whereas, wide excision improves the prognosis.