*2.2. Histological Inclusion/Exclusion Criteria*

The detailed inclusion/exclusion criteria were described in recent studies [23,25]. Briefly, for the NIFTP subgroup, the inclusion criteria included major features (encapsulation/clear demarcation, follicular growth pattern, nuclear features of PTC (2–3 points of the 3-point nuclear scoring scheme): enlargement, crowding/overlapping, elongation, irregular contours, grooves, pseudoinclusions, chromatin clearing) [37] and minor features (dark colloid, irregularly shaped follicles, intratumoral fibrosis, "sprinkling" sign, follicles cleft from stroma, multinucleated giant cells within follicles) [11]. The exclusion criteria used for NIFTP were the presence of "true" papillae, psammoma bodies, infiltrative border, tumor necrosis, high mitotic activity, cell/morphologic characteristics of other variants of PTC. EFVPTC with different degrees of capsular transgression exhibited features within an encapsulated or well circumscribed nodule, follicular architecture, PTC nuclear features and papillae [37]. Noninvasive FVPTC with lymphocytic/Hashimoto's thyroiditis (LT) histologically presented with extensive lymphocytic infiltrate with germinal center formation, lymphocytes predominantly and plasma cells, atrophic follicles with abundant Hürthle cells (large, polygonal cells with abundant granular eosinophilic cytoplasm and large hyperchromatic round to oval regular nucleus). Therefore, LT was placed in a separate category to avoid possible false positive interpretation of a co-existing inflammatory environment as a factor in Gal-3 cytoplasmic expression [37–39].
