Malignant fibrous histiocytoma

Malignant fibrous histiocytomas are tumours arising from primitive mesenchymal cells which occur predominantly in soft tissues, most often in relation to skeletal muscle. Like benign fibrous histiocytomas, they are composed of a mixture of cells resembling myofibroblasts, fibroblasts, histiocytes, primitive mesenchymal cells, and cells having intermediate or mixed features.

• malignant fibrous histiocytomas account for 20-30% of soft tissue sarcomas
• they affect all age groups, with a peak incidence in the seventh decade. The incidence is slightly higher in males
• sites of origin of malignant fibrous histiocytomas
  • lower extremities (approx. 50%)
  • upper extremeties (approx. 20%)
  • abdominal cavity including retroperitoneum (approx. 20%)
• majority arise in relation to skeletal muscle; occasionally they involve the deep fascia or less often the subcutaneous tissue; the osseous tumours occur more commonly around the knee