Predictive factors for malignancy in cytologically diagnosed oncocytic cell neoplasm of the thyroid: A single-center analysis

Oncocytic (Hurthle) cell neoplasms (OCNs) of the thyroid are follicular-derived lesions characterized by abundant eosinophilic cytoplasm due to mitochondrial accumulation. Fine-needle aspiration (FNA) cytology is a primary diagnostic tool for thyroid nodules but struggles to distinguish benign from malignant OCNs, leading to potential overtreatment. Identifying preoperative predictors of malignancy may improve risk stratification. A retrospective review was conducted at Chi Mei Medical Center from January 2012 to December 2023. Patients with a FNA diagnosis of OCN and subsequent thyroidectomy were included. Demographic data, ultrasound characteristics (tumor size and TIRADS classification), and final histopathological diagnoses were analyzed. Logistic regression models assessed predictors of malignancy (P < 0.05). Of 1998 patients with thyroid nodules exhibiting oncocytic features on FNA, 174 met the inclusion criteria. Malignancy was confirmed in 28 cases (16.1 %), with oncocytic carcinoma accounting for 21 % of malignant cases. Gender and TIRADS classification were not significantly associated with malignancy risk. Tumor size was a significant predictor, with a cutoff of 1.83 cm demonstrating an adjusted odds ratio (AOR) of 4.22 (95 % CI: 1.18–15.09, P = 0.0268) for malignancy. Preoperative differentiation between benign and malignant OCNs remains challenging. Smaller tumor size is associated with a significant risk of malignancy. Given their potential for distant metastasis and resistance to radioactive iodine therapy, diagnostic lobectomy remains the preferred approach for the management of OCNs.