Angiomatoid malignant fibrous histiocytoma: cytologic, immunohistochemical, ultrastructural, and flow cytometric study of 20 cases.

Twenty examples of angiomatoid malignant fibrous histiocytoma (AMFH) were studied. Patients ranged in age from 3 mo to 42 yr, with a mean of 13.4 yr (median 10.5 yr). There were 12 males and eight females. Tumors occurred in the upper extremities in eight cases, lower extremities in 10 cases, and one case each in the buttock and neck. Five patients had local recurrence from 5 to 18 mo after initial surgery, and one patient developed regional lymph node metastases and eventually died of disease. Eight of nine patients with follow-up information were alive from 11 to 31 mo after the diagnosis. Preoperative fine needle aspiration cytology performed in two patients showed features that suggested the correct diagnosis. Ultrastructural and immunohistochemical studies demonstrated findings consistent with a fibroblastic-histiocytic nature of the neoplasm and failed to detect endothelial differentiation of the tumor cells. Flow cytometric analysis performed in six cases, including three recurrent tumors, revealed a DNA diploid pattern in all instances. AMFH appears to be a distinctive low grade sarcoma in the spectrum of malignant fibrous histiocytoma.