[The ultrastructure and histochemical characteristics of the cells of malignant fibrous histiocytoma in rats].

Samples of tissue from malignant fibrous histiocytoma of rats induced by subcutaneous injection of paraffin pill-enclosed DMBA were studied for localization of acid phosphatase and non-specific esterases (15 samples) and cell ultrastructure (10). Tumours showed cellular heterogeneity consisting of 5 types of cells: histiocyte-like, fibroblast-like, giant multinuclear xanthomatous and undifferentiated. Acid phosphatase and non-specific esterases were found both in histiocyte-like and fibroblast-like cells which means that those enzymes are not the specific markers of tumors arising from monocytic-macrophagal system. Histochemical and ultrastructural features of experimental malignant fibrous histiocytoma were similar to those of its human analogue.