Endocrine Abstracts

JOINT3647

Objective: This study aims to evaluate the postoperative pathology results of thyroid nodules with Bethesda Category IV cytology. The study also seeks to determine the malignancy rate, tumor subtypes, and the surgical approach of these patients.

Methods: A retrospective analysis was conducted on patients who underwent fine needle aspiration biopsy (FNAB) at Ankara Bilkent City Hospital and were classified under Bethesda Category IV. Demographic data, preoperative thyroid function tests, ultrasound characteristics, and surgical interventions were reviewed. Postoperative pathology results were analyzed to determine malignancy rates and tumor characteristics.

Results: 104 patients with FNAB result of Bethesda Category 4 were examined. 70 patients whose postoperative pathology was available were included in the study. In the classification of patients according to gender, 56 (53. 8%) patients were female and 14 (13. 5%) patients were male. The mean age was 46. 68±13. 99. FNAB cytology subtypes were follicular neoplasm suspicious (74. 3%), follicular neoplasm (%4. 3) and Hurthle cell neoplasm (21. 4%). Bilateral total thyroidectomy was performed in 62 patients (% 88. 6), right lobectomy in 5 patients (% 7. 1), and left lobectomy in 3 patients (%4. 3). Of the 70 patients, 26 (37. 2%) had malignant tumors, with papillary thyroid carcinoma being the most common malignancy (84. 6%). Pathology of 11 patients (%15. 7) was papillary carcinoma follicular variant, and pathology of 1 patient (%1. 4) was papillary carcinoma oncocytic variant. Other malignancies included follicular carcinoma (%2. 9) and Hurthle cell carcinoma (%2. 9).

Conclusion: The overall malignancy rate in patients with Bethesda Category IV cytology was 37. 2%, with papillary thyroid carcinoma being the most commonly diagnosed malignancy. Our malignancy rate in Bethesda category 4 is consistent with the literature; however, the final histopathological diagnoses of the lesions in this category were more commonly reported as classical papillary thyroid carcinoma (PTC) rather than follicular variant PTC or follicular cancer. This suggests that pathologists should review and reassess their reports for Bethesda category 4 lesions.