Introduction: Giant cell fibroblastoma is a rare mesenchyma tumor of childhood having many similarities with dermatofibrosarcoma protuberans in adults.
Observation: We report the case of a 28-year-old woman presenting a subcutaneous inter-mammary mass associating both tumors. Immunohistochemistry showed an expression of CD 34 only by dermatofibrosarcoma protuberans cells.
Discussion: It is important to stress: the rarity of this association, the difficulty to confirm the diagnosis and to establish the links between these two tumors: simple association (as in our case), transformation or recurrence of giant cell fibroblastoma in dermatofibrosarcoma protuberans.