Endocrine Abstracts

Morphologically, the follicular cells of the thyroid gland on the background of chronic lymphocytic (Hashimoto) thyroiditis may exhibit atypical changes in the nucleus, expansion of the nucleus, crowding, irregularities of nuclear membranes, intranuclear grooves and purification of chromatin. Also be observed proliferative foci of thyroid follicular cells with follicular epithelial dysplasia (FED) were as presumed premalignant conditions in chronic lymphocytic thyroiditis. These foci with Hashimoto Thyroiditis (HT), which differ from the surrounding parenchyma, are less than 0.1 cm in size, do not have invasive growth, the structure of the papillary thyroid gland or intranuclear pseudo inclusions were considered as presumed premalignant conditions in chronic lymphocytic thyroiditis. Also, FED foci exhibit an immunohistochemical (IHC) profile similar to papillary thyroid carcinoma (PTC). Observation was carried out on operative materials. A total 59 cases (37 patients with HT and 22 patients with PTC in HT background). Paraffin embeded and Hematoxylin and Eosin stained samples were used for histopathological examination. IHC staining was performed on Formalin-fixed paraffin embedded tissue sections with antibodies against the following markers: 1. Thyroid transcription factor 1 (TTF1); 2. CD56; 3. p63. As control - histochemical panel: 1. CK19, 2. Cyclin-D1, 3. Galectin-3. With the results obtained, the main histopathological discovery in HT was the atrophy of the thyroid parenchyma, accompanied by lymphoid infiltration, lymphoid follicular hyperplasia, the formation of a secondary germinal center and an abundance of macrophages and plasma cells. Foci of thyroid follicular cells with atypical nuclear features (dysplastic foci) were also seen. In cases of HT without associated PTC, immunoreactivity from moderate to severe p63 was found throughout the thyroid parenchyma, including thyroid follicles, as well as squamoid regions, which is consistent with solid nest cells. In our study, Similar pattern of CD56 and p63 immunoreactivities was observed in foci of PTC arising in the background of HT - strong diffuse staining of Galectin-3 (40%), Cyclin-D1 (70%). Particularly noteworthy is the negative response to CD56 immunostaining in the HT regions of the dysplastic epithelium (FED): Thyroid nuclei showed atypical signs, but versus lymphocytic thyroiditis (40%), they did not have a set of PTC nuclear markers (26%). We can conclude, that the panel of these immunomarkers can potentially be used as a diagnostic tool to differentiate these two forms of thyroiditis, as well as to predict the risk of developing PTC, especially during preoperative evaluation in small diagnostic tissue samples.