[Malignant fibrous histiocytoma of the bone]

The data of clinico-morphological study of 10 observations of malignant fibrous histiocytoma of the bone indicating its distinct nosological importance are presented. Clinico-morphological comparisons showed the typical variant of the morphological structure to have the worst prognosis. In two observations, the tumor was examined electron microscopically. All the 5 main types of cells were found: histiocyte- and fibroblast-like, giant multinuclear, xanthomatous, and poorly-differentiated mesenchymal. In one case, intranuclear virus-like inclusions of the herpesvirus type were found. Their presence in 4 main types of cells suggests their common histogenetic origin from poorly-differentiated mesenchymal cells.