FINE NEEDLE ASPIRATION OF HÜRTHLE CELL NEOPLASMS OF THE THYROID: A CLINICOCYTOMORPHOLOGIC STUDY

SUMMARY Cytologic diagnosis of Hürthle cell neoplasm (HCN) includes both Hürthle cell adenoma (HCA) and Hürthle cell carcinoma (HCC). They are indistinguishable on the basis of cytologic examina-tion because the criteria of malignancy are based on tissue architectural features of capsular and/or vascular invasion. All patients with subsequent histopathologic diagnosis of HCN of the thyroid and preoperative cytologic evaluation by fine needle aspiration (FNA) during the last six years were studied for a number of cytomorphologic features and clinical parameters (age, gender and nodule size) to determine the factors predictive of carcinoma. There were 17 cases in total, including 4 HCC and 13 HCA cases. Carcinoma was diagnosed in three of 13 (23%) women and in one of four (25%) men. Age range was 32-75 (median 57) years in adenoma patients and 46-70 (median 58) years in carcinoma patients. The mean tumor size was 4.5–3.41 cm and 3.07–1.82 cm in HCC and HCA patients, respectively. The cytomorphologic features indicative of HCC versus HCA were syncytial clusters and Hürthle cells with large nucleoli, whereas Hürth-le cells showing pronounced nuclear and cellular pleomorphism in monolayered sheets with small nucleoli appeared to be characteristic of HCA (p<0.05 both). The presence of Hürthle cells in syncytial clusters with large nucleoli in thyroid nodule FNA should alert the observer of the possible HCC