RESUMO
263 tumors diagnosed as malignant fibrous histiocytomas and undifferentiated pleomorphic sarcomas have been reassessed morphologically, immunohistochemically and ultrastructurally. The diagnosis of pleomorphic fibrosarcoma was made in 19 patients (5%). The tumors occur in the lower and upper extremities and trunk. The patients have a long history of painless intramuscular mass (for a median of 6 months). Follow up showed disease recurrence in 24% of patients and metastases in 32% of patients. All tumors consisted of spindle-shaped fibroblasts and myofibroblasts with a prominent rough endoplasmic reticulum and Golgi apparatus, extracellular collagen fibrils. Variable number of histiocite-like fibroblasts and undifferentiated cells were found. No other signs of tumor cell line differentiation were noted. A pleomorphic fibrosarcoma and malignant fibrous histiocytoma have similar clinical and radiographic manifestation and survival rates.
