Atypical fibrous histiocytoma, malignant fibrous histiocytoma, malignant histiocytoma, and epithelioid sarcoma.A comparative study of 65 tumors

Abstract

This study concerns 65 patients with fibrohistiocytic tumors that microscopically had a bizarre and often malignant appearance. Four histologic types were recognized: atypical fibrous histiocytoma (18 tumors), malignant fibrous histiocytoma (33 tumors), malignant histiocytoma (seven tumors), and epithelioid sarcoma (seven tumors). Twenty-one of the tumors (18 malignant) evolved from the superficial tissues and 44 (29 malignant) from the deep soft tissues. Local recurrences were noted in 73% of the patients treated by local excision. Metastases occurred in 19 patients (regional lymph nodes in 13 instances and lungs in 14 instances). Five-year survival rates were 90% for the group with atypical fibrous histiocytoma, 64% for the group with malignant fibrous histiocytoma, 50% for the group with malignant histiocytoma, and 100% for the group with epithelioid sarcoma; the 10-year survival rates were 80%, 38%, 0%, and 80%, respectively. Although everyone may not agree with the concept of tissue histiocyte origin, the lesions do present a definite histologic range with recognizable transitions from the atypical through the malignant forms.