[Sclerosing epithelioid fibrosarcoma]

The sclerosing epithelioid fibrosarcoma (SEF), defined as an entity by Meis-Kindblom et al. in 1995 [15] is now considered to be a variant of fibrosing fibrosarcomas. It is a rare tumor with an intermediate malignant potential leading to local recurrences in one third and to metastases in about 40% of the cases. We report six cases of this entity. At the time of diagnosis two patients of our series already showed metastases in the lungs. The tumors were located in the deep soft tissue and measured between 2.5 and 17 cm. The histology is characterized by small epithelioid cells that are arranged individually or in cords and nests and set typically in a hyaline sclerotic matrix. By immunohistochemistry, all cases were vimentin positive, however EMA positive cells are also possible. The differential diagnosis includes metastases of carcinoma, benign and malignant soft tissue tumors. The distinction of SEF from fibromatosis, fibrous histiocytomas, ossifying fibromyxoid tumors, clear cell sarcomas, epithelioid sarcomas, synovial sarcomas and extraskeletal osteosarcomas is discussed.