Analyzing the correlation between low proportion of hobnail features in papillary thyroid carcinoma and clinical aggressiveness risk.

Purpose: Hobnail features may enhance the clinical aggressiveness of papillary thyroid carcinoma (PTC). However, whether a low proportion (<30%) of these features contributes to increased PTC aggressiveness remains unclear. This study investigated whether PTC cases with a low proportion hobnail features (<30%) exhibit clinical invasiveness and pathological features of aggressiveness.

Methods: Pathological specimens from patients with postoperatively diagnosed PTC were retrospectively analyzed. Among them, 29 PTC cases with a low proportion of hobnail features (<30%) were compared with 173 consecutive classical PTC (cPTC) cases. Data regarding age at presentation, sex, tumor size, number of tumors, and histological characteristics were obtained by reviewing electronic medical records. Postoperative information was obtained during follow-up visits and telephone interviews.

Results: Twenty-nine patients with PTC with a low proportion of hobnail features (<30%) were identified, exhibiting a median age of 34 years. At a median follow-up of 31 (IQR, 23-37) months, two patients had recurrent disease in the PTC with a low proportion of hobnail features (<30%) group, whereas there was no recurrence in the cPTC group. No distant metastasis and postoperative mortality were observed in either group. Compared with the cPTC group, patients with PTC and a low proportion of hobnail features exhibited larger tumor volumes and higher susceptibility to capsular invasion and lymph node metastasis. Tumor size and hobnail features emerged as independent risk factors for lymph node metastasis.

Conclusion: PTC with a low proportion hobnail features (<30%) and larger tumor volumes are associated with the occurrence of lymph node metastasis. A low proportion of hobnail features (<30%) in PTC may heighten invasiveness, elevating the risk of recurrence.