Abstract
CONTEXT: Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, generally associated with a favorable prognosis. However, variants such as the hobnail subtype exhibit more aggressive pathological and clinical features. OBJECTIVE: The 2022 WHO classification defines hobnail PTC (HPTC) as tumors with at least 30% hobnail cell morphology, yet the prognostic impact of varying hobnail cell proportions remains unclear. DESIGN: This study aimed to evaluate the clinicopathological characteristics and prognostic significance of PTC with different degrees of hobnail features, contributing to improved risk stratification and management strategies. SUBJECTS AND METHODS: A comprehensive analysis was conducted on PTC cases exhibiting hobnail features at varying proportions. Pathological characteristics, including vascular and lymphatic invasion, calcification, lymph node metastasis, and capsule involvement, were assessed. Logistic regression analysis was performed to determine associations between hobnail morphology and aggressive disease behavior. RESULTS: Tumors with ≥30% hobnail features exhibited significantly (p< 0.05) higher rates of vascular invasion, lymphatic invasion, calcification, and lymph node metastasis compared to tumors with fewer hobnail features and classic PTC. Logistic regression confirmed a strong association between hobnail morphology and lymphatic invasion/metastatic lymph nodes (p = 0.026). However, no significant correlation (p>0.05) was observed with extrathyroidal invasion, bilaterality, or the necessity of radioactive iodine (RAI) treatment. CONCLUSION: The findings emphasize the aggressive nature of PTC with prominent hobnail features, underscoring the need for tailored therapeutic strategies and close monitoring in affected patients. Further research is warranted to refine prognostic models and optimize treatment approaches.