[Sclerosing epithelioid fibrosarcoma: a fibrosarcoma with a very long course]. / Le fibrosarcome épithélioïde sclérosant: un fibrosarcome d'évolution très lente.

Sclerosing epithelioid fibrosarcoma is a rare and slowly growing variant of fibrosarcoma occurring in adults. Its carcinomatous and/or hemangiopericytomatous patterns may mislead to many different tumors. These differential diagnoses are generally ruled out by the clinical data, the morphology and the immunohistochemical study. We report two typical cases of this fibrosarcoma and we highlight the different criterias which are indispensable to make the diagnosis. The very slow course of this disease goes along with a very low proliferative rate, but an accumulation of p53 by immunohistochemistry is paradoxically always founds, even though this accumulation is more often found in highly aggressive sarcomas.