[Ewing's sarcoma (electron microscopy study)].

Ewing's tumor is a rare malignant neoplasm of the bone the histogenesis of which still remains obscure. The present study was aimed at the electron microscopic determination of the structural characteristics of the neoplasm' cell elements. Tumor tissue from 4 patients operated on elements. Tumor tissue from 4 patients operated on at the Cancer Research Centre of the USSR AMS was examined. The methodical approach was modified in this study: with due account to the zonal distribution of organelles in tumor cells of the bone, 100 preparations from one block were examined in the electron microscope. The tumor cell elements were shown to be predominantly forms of low differentiation. Detailed examinations revealed signs of structural-functional differentiation of the cells mostly indicative of the angiogenic nature of Ewing's tumor.