Preoperative, operative, and postoperative pathological features in thyroid papillary carcinoma with and without capsule invasion

Aims: Approximately 80-85% of thyroid malignancies are papillary thyroid cancer (PTC).This study evaluated the relationship between thyroid capsule invasion (TCI) in PTC and macroscopic histopathological findings.Methods: A single-center, retrospective study was conducted using the medical records of adult patients who underwent PTC surgery.The patients were classified as TCI (+) or TCI (-) based on the postoperative pathological examination.Tumor localization, calcification, and multifocality were evaluated between the two groups. Results:The study included 236 patients (mean age: 44.3±12.0years, female sex: 76.7%).Preoperative basic characteristics, comorbidities, thyroid function status, nodule calcification, halo border irregularity, and nodule diameter on ultrasonography were similar between the two groups.However, more TCI (+) patients had positive or suspicious fine needle aspiration biopsy findings preoperatively.The duration of surgery was longer in TCI (+) patients (86 minutes vs. 75 minutes, p<0.001), whereas the length of hospital stay was similar.Surgical margin >1 mm was more common in TCI (+) vs. TCI (-) patients (47.3% vs. 81.8%,p<0.001).Postoperative macroscopic pathological reports showed that middle lobe tumor localization was more common in TCI (+) (38.2%) than in TCI (-) (23.2%) patients (p=0.028),whereas tumor localization in the upper pole, lower pole, and isthmus was not different.Multifocal involvement (41.8% vs. 38.1%)was also similar between the two groups.Conclusions: This study showed that fine needle biopsy positivity and nodule localization in the middle thyroid gland were more common in TCI (+) PTC patients as detected postoperatively.The other macroscopic pathological findings were not different.