Morphological and immunohistochemical evaluation of interface lesions between chronic lymphocytic thyroiditis and papillary thyroid cancers

Objective: To evaluate the expression of papillary thyroid carcinoma-associated tumor markers in reactive and dysplastic changes showing papillary thyroid carcinoma-like nuclear features in chronic lymphocytic thyroiditis cases. Material and Method: In this study, we retrospectively analyzed 84 cases diagnosed with chronic lymphocytic thyroiditis based on the analysis of thyroidectomy specimens in our center over the last five years. We classified them as normal, reactive and dysplastic changes and performed an immunohistochemical analysis using HBME-1, Galectin-3, Cytokeratin 19, and Cyclin D1. Results: The mean age of the patients was 45.5 years, and 68 were female and 16 were male. According to the morphological features, 42.9% of the were classified to have normal morphology, 44.0% reactive atypia, and 13.1% follicular epithelial dysplasia (FED). Of the chronic lymphocytic thyroiditis cases, 42.9% were associated with malignancy, with the most common accompanying malignancy being papillary thyroid cancer (36.9%). Immunohistochemically: for HBME-1, FED (72.7%) was higher (p