Papillary Thyroid Carcinoma with Different Histological Patterns

Tumor-node-metastasis (TNM) staging is the most commonlyused model for evaluating therapeutic strategies forpapillary thyroid cancer (PTC). Additionally, differenthistopathological patterns and variants of PTC have beenreported to influence the prognosis of these patients. Wereviewed the clinical presentation, cancer recurrence, and cancer-specific mortality of the most frequent histological patterns,including the follicular variant (FVPTC), insular pattern,tall cell pattern, diffuse sclerosing type, PTC with Hashimoto’sthyroiditis, and multicentric PTC. The tall cell variant of PTCis a more aggressive variant than classical PTC and has a poorprognosis. The high expression of Muc1 and type IV collagenasein these tumors may facilitate stromal degradation andincrease the invasive potential. In contrast, approximately 18%of PTC patients have been identified as having FVPTC.FVPTC patients have a better survival rate than those with follicular thyroid cancer, andfewer instances of lymph node or soft tissue invasion than control patients with classicalPTC. The diffuse sclerosing variant of PTC predominantly observed in young patients is arare aggressive tumor that requires intensive treatment. Despite characteristic clinical andhistological features that facilitate easy diagnosis, pre-operative fine needle aspiration cytologicaldiagnosis of this variant is often challenging. Different histological variants of PTCwith other histological patterns are important for predicting cancer recurrence. In addition toTNM staging, high-risk histological patterns of PTC require more aggressive follow-upexaminations and postoperative adjuvant therapies.