MALIGNANT MESENCHYMOMA

BACKGROUND. Malignant mesenchymomas are rare soft tissue tumors that c ontain two or more distinct histologic subtypes of sarcoma within the same tumor (exclusive of a fibrosarcomatous or hemangiopericytomatous component). They are generally considered high grade neoplasms and are associated with a poor prognosis, although experience with these tumo rs is limited. METHODS. We report 8 patients seen at our center over t he last 22 years and describe the clinical course of a patient with a malignant mesenchymoma arising in the retroperitoneum whose experience typifies the aggressive behavior of this tumor. RESULTS. All eight pa tients had large, high grade tumors located in the retroperitoneum or thigh. Six of the 8 died of disease and 2 were alive with disease at a median of 30 months from diagnosis. CONCLUSIONS. Malignant mesenchymo ma represents a particularly aggressive form of soft tissue sarcoma. O ur experience with this disease highlights the need for more effective treatment strategies for these patients. (C) 1996 American Cancer Soc iety.