Cytology of Hürthle cell neoplasms of thyroid gland

Hürthle cell neoplasms (HCN) are an uncommon group of tumors of the thyroid gland. Fine needle aspiration cytology (FNAC) is an important diagnostic tool in solitary nodules of the thyroid gland. A 5-year retrospective analysis of all cases diagnosed as HCN on cytology was performed and correlated with the corresponding histopathology wherever available. There were 13 cases diagnosed as HCN out of which 6 cases had subsequent histopathologic examination. Four were adenomas and two were carcinomas. In addition, 3 cases that were adenomas on histopathology were reported on cytology as colloid goiter with cystic degeneration in 2 cases and as follicular adenoma in 1 case. There was extensive cystic degeneration in the former two cases whereas poor cellular preservation led to misdiagnosis in the third case. There were no specific cytomorphological features that distinguished adenoma from carcinoma. FNAC has a high specificity for a diagnosis of HCN, but the sensitivity is not as high because of sampling error.