ABSTRACT
Malignen change in dermatofibrosarcoma protuberans is a rare phenomenon. We present one case. A patient operated for local recurrences of dermatofibrosarcoma. The histopathological study showed a fascicular and highly cellular histological pattern in the dermis, with important mitotic activity. Sometimes the nucleus was central chow small indentations produced by multiple small vacuoles like a lipoblast, with an extensive capillary network appearance the diagnosis of liposarcoma was proposed. Malignen change of dermatofibrosarcoma is defined by it herringbone architecture, hypercellularity, and increased mitotic rate. Occasionally, can lead to misdiagnosis with other spindle-cell tumors especially liposarcoma which has a worse prognosis. Multiple sampling and immunohistochemistry with antibody CD34 help to establish the right diagnosis. The degree of aggression is related to the histological grade and of sarc omatous transformation. The prognosis of the transformed dermatofibrosarcoma is more aggressive than the classic than one in liposarcoma