The prevalence and surgical outcomes of Hürthle cell lesions in FNAs of the thyroid: A multi‐institutional study in 6 Asian countries

• Published in: Cancer cytopathology 2019-03, Vol.127 (3), p.181-191
• Main Authors: Agarwal, Shipra, Bychkov, Andrey, Jung, Chan Kwon, Hirokawa, Mitsuyoshi, Lai, Chiung‐Ru, Hong, SoonWon, Kwon, Hyeong Ju, Rangdaeng, Samreung, Liu, Zhiyan, Su, Peng, Kakudo, Kennichi, Jain, Deepali
• Format: Article
• Language: English
• Subjects: Adenoma, Oxyphilic - epidemiology; Adenoma, Oxyphilic - pathology; Adenoma, Oxyphilic - surgery; Adolescent; Adult; Asia - epidemiology; atypia of undetermined significance/follicular lesion of undetermined significance; Biopsy, Fine-Needle - methods; Cytodiagnosis - methods; Cytodiagnosis - statistics & numerical data; Female; fine‐needle aspiration (FNA); follicular neoplasm; Humans; Hürthle cell lesion; Hürthle cell neoplasm; Hürthle cell type; Male; Outcome Assessment, Health Care - methods; Outcome Assessment, Health Care - statistics & numerical data; Oxyphil Cells - pathology; Prevalence; Retrospective Studies; risk of malignancy (ROM); risk of neoplasia (RON); the Bethesda System for Reporting Thyroid Cytopathology; Surgical outcomes; Thyroid cancer; Thyroid gland; Thyroid Gland - pathology; Thyroid Gland - surgery; Thyroid Neoplasms - pathology; Thyroid Neoplasms - surgery; Thyroid Nodule - pathology; Thyroid Nodule - surgery
• ISSN: 1934-662X; 1934-6638
• DOI: 10.1002/cncy.22101

Background Hürthle cell‐rich nodules (HCNs) encompass non‐neoplastic to malignant lesions. There is paucity of literature on the frequency distribution of HCNs among Bethesda categories, histologic follow‐up, risk of malignancy (ROM), and risk of neoplasia (RON). The objective of this retrospective, multi‐institutional study was to determine the prevalence of the cytologic diagnostic category and surgical outcomes of patients with HCN. Methods Nine tertiary health centers representing 6 Asian countries participated. Cases were retrieved from respective databases. The Bethesda System for Reporting Thyroid Cytopathology was used. Cytology results were correlated with surgical diagnoses. Results Of 42,190 thyroid aspirates retrieved, 760 (1.8%) had a Hürthle cell predominance. Most (61%) were categorized as atypia of undetermined significance/follicular lesion of undetermined significance, Hürthle cell type” (AUS‐H); 35% were categorized as follicular neoplasm, Hürthle cell type (FN‐H); and 4% were categorized as suspicious for malignancy (SFM). Histologic follow‐up was available for 288 aspirates (38%). Most were benign on resection (66%), and the most common histologic diagnosis was Hürthle cell adenoma (28.5%). The ROM for AUS‐H, FN‐H, and SFM, as calculated on resected nodules, was 32%, 31%, and 71%, respectively; and the RON was 47%, 81%, and 77%, respectively. The 5 institutions that had an AUS‐H:HCN ratio below 0.5 diagnosed HCN less frequently as AUS‐H than as FN‐H. Conclusions This is the largest, contemporary, multi‐institutional series of HCNs with surgical follow‐up. Although there was wide interinstitutional variation in prevalence and surgical outcomes, there was no significant difference in the ROM among institutions. The categories AUS‐H and FN‐H had a similar ROM for resected nodules. In a large, multi‐institutional study of Hürthle cell–rich lesions with surgical follow‐up, the incidence of Hürthle cell nodules, their Bethesda categorization on aspiration cytology, and the risks of malignancy and neoplasm are highlighted.