[Pressing problems in the study of the pathological anatomy of epithelial thyroid gland tumors].

The paper analyses most important publications and the author's own observations on the pathology of the thyroid gland epithelial tumours. The WHO Histological classification of tumours of the thyroid gland was used for the analysis of the material, although on the basis of his own studies the author concludes that apart from the benign thyroid gland tumours mentioned in the classification, atypical and papillary adenomas, adenoma of Ashkinazi cells and benign tumour consisting of C-cells should be distinguished. In the morphological diagnosis of highly differentiated carcinoma tumours the greatest importance is attributed to the structure of the nucleus of tumour cells the structure of which have been studied both by light and electron microscopy. The latter is also very important for histogenetic diagnosis of undifferentiated carcinoma and tumours consisting of C-cells. The tumour cells rich in mitochondria in which the activity of oxidative-reductive enzymes is high are considered as cells undergoing degeneration due to cytotoxic effect of lymphocytes.