KRT19 and differentiated thyroid carcinoma: The concept of follicular epithelial dysplasia has been proposed for the foci of papillary thyroid carcinoma-like cytologic atypia and architectural distortion associated with lymphocytic thyroiditis based on the expression pattern of papillary carcinoma immunohistochemical markers (HBME-1, cytokeratin 19, Galectin-3) [17–19], while low-level CCDC6-RET and NCOA4-RET fusion in Hashimoto thyroiditis-related follicular cells also points to a possible follicular cell atypia-dysplasia-to-carcinoma progression sequence in the setting of lymphocytic thyroiditis [20].