Does the fine-needle aspiration diagnosis of "Hürthle-cell neoplasm/follicular neoplasm with oncocytic features" denote increased risk of malignancy?

The thyroid fine-needle aspiration (FNA) diagnosis of Hürthle-cell neoplasm (HCN)/follicular neoplasm with oncocytic features (FNOF) does not differentiate between Hürthle-cell adenoma and carcinoma. A majority of cases diagnosed as HCN undergo surgical excision for definite characterization. The aim of this study was to determine the risk of malignancy in cases diagnosed as HCN and identify clinical features that may help in predicting malignancy in patients with FNA diagnosis of HCN. We reviewed a cohort of 206 cases of thyroid FNA diagnosed as HCN; histological follow-up was available in 169 (82%) cases. The cases were evaluated for patient's age, sex, and size of the nodule and histological diagnosis. One hundred and sixty-six were female patients and 40 were male patients (age range, 12-83 yr). The histological diagnoses were benign in 93 (93/169, 55%) cases and malignant in 76 (76/169, 45%) cases. The malignant histological diagnoses were Hürthle-cell carcinoma (HCC), 53 cases; papillary thyroid carcinoma, 19 cases; follicular carcinoma, 3 cases; and medullary carcinoma, 1 case. The risk of malignancy was greater in nodules measuring > or =2 cm (55% vs. 45%; P value < 0.0001) in patients who were > or =40 yr old (82% vs. 18%, P value < 0.0001) than in patients <40 yr. The risk of malignancy was found greater in male patients than in female patients (61% vs. 43%); however, the difference was not statistically significant. The diagnosis HCN/FNOF carries a higher risk of malignancy as compared with a diagnosis of follicular lesion/neoplasm (20% malignancy rate from previously published studies). Clinical features including size of the nodule, age, and possibly sex of the patient can be a part of the decision analysis in selecting a patient for surgery.