Malignant Fibrous Histiocytoma and Macrophage Differentiation.

Abstract

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of adult life. Its clinicopathological entity, however, is not completely established because of its uncertain histogenesis. In this review, the histogenesis of MFH is discussed through an overview of the concept of macrophage ontogeny. Our recent multiparametric studies indicate that MFH is a tumor of mesenchymal cells with fibroblastic differentiation.Histiocyte-like cells in the tumor are considered to be not neoplastic component but infiltrated macrophages. Because this tumor is not one of the histocytes or macrophages, the term " malignant fibrous histiocytoma" is inappropriate.Instead, this tumor should be renamed as a special type of mesenchymal cell tumor differentiating toward fibroblasts and producing monocyte chemoattractants and macrophage differentiation factors.