[Ultrastructural characteristics of the histological forms of breast tumors].

Differences in ultrastructurally-differentiated and undifferentiated cells distribution were established in such non-invasive and invasive histological patterns of breast cancer as medullar carcinoma, mucinous, adenoid-cystic and lobular invasive cancer by means of electron microscopy. It was shown that a certain histological pattern is not necessarily matched by a relevant degree of ultrastructural differentiation of tumor cells. Tumor tissues of a similar histological pattern sometimes revealed different ratios of ultrastructurally-differentiated and undifferentiated cells, which may be responsible for the peculiarities in the clinical behavior of the said neoplasms. These data should be taken into account in establishing ultrastructural diagnosis as well as prognostic evaluation of the findings of electron microscopic examination in cases of non-invasive and certain invasive forms of breast tumors.