Frequency of combinations of different histological forms of papillary thyroid cancer with other diseases of the thyroid parenchyma

The authors showed that in the prevailing majority of cases (71 %) papillary carcinomas were formed against the background of other thyroid diseases. In this work, the main forms of thyroid pathology, which is most often found in PTC, were identified and their frequency was determined. It has been proven that in 39.8 % of cases PTC was combined with only one of the following diseases: in 20 % with autoimmune thyroiditis, in 14.8 % with colloid goiter, in 5 % with follicular adenomas. The combination of PTC with not one, but with several thyroid pathologies is 31.4 %. Such a high frequency of combination of malignant and benign pathology in the thyroid gland suggests that the proliferative processes that result in benign diseases can change their direction and lead to the appearance of cells with signs of malignancy. That is, goitre-altered thyroid tissue is more sensitive to the action of various carcinogenic agents, such as radiation, toxic effects or impaired neuroendocrine regulation. In the analysis of histological forms of PTC, it was shown that AIT is more common in adenocarcinomas and PC from cylindrical cells, and colloid goiter in microscopic cancer and follicular PC. Follicular adenoma is more often associated with follicular PTC. We believe that the analysis will have value for the differential diagnosis of histological forms of papillary thyroid cancer.