Fibroblast and Myofibroblast Participation in Malignant Fibrous Histiocytoma (MFH) of Bone

Eight malignant fibrous histiocytomas (MFH) of bone were studied with immunohistochemistry and electron microscopy. Ultrastructurally, fibroblasts and myofibroblasts were the main tumor cells in four cases and abundant in two other cases; these cells showed immunohistochemical positivity to alpha 1-antitrypsin, vimentin and anti-muscle antigen (HHF 35). Moreover, histiocytic-like tumor cells were electron-microscopically detected in four cases, being the main tumor cell type in two of the cases; immunohistochemically these cells expressed positivity to alpha-1-antichymotrypsin (A1ACT), alpha-1-antitrypsin (A1AT) and vimentin. Present results confirm the cellular heterogeneity of MFH of bone…