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

Abstract

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.

Hürthle cell neoplasms of the thyroid: Pathologic outcomes and ultrasonographic analysis

“…The overall rate of thyroid malignancy was 15.1%; this included oncocytic variants of other types of thyroid malignancy. This is consistent with rates previously described 10‐14 . Of the patients who underwent an initial hemithyroidectomy and were found to have malignancy, 23.1% were found to have a contralateral malignancy after completion thyroidectomy.…”

“…This is consistent with rates previously described. [10][11][12][13][14] Of the patients who underwent an initial hemithyroidectomy and were found to have malignancy, 23.1% were found to have a contralateral malignancy after completion thyroidectomy. These findings can be incorporated into patient counseling and management.…”

“…Hemithyroidectomy patients found to have malignancy on surgical pathology are typically offered completion thyroidectomy 9 . Rates of thyroid malignancy found in patients who undergo surgery range from 14% to 46% 10‐14 …”

“…9 Rates of thyroid malignancy found in patients who undergo surgery range from 14% to 46%. [10][11][12][13][14] The wide range in rate of malignancy raises questions for prognosis, optimal management, and patient counseling. Prior research has identified male sex and older age as predictors of malignancy in HCN.…”

Thyroid fine-needle aspiration cytology in Taiwan: a nationwide survey and literature update

“…Lee et al [32] reported that 60% of surgical cases with HTC were designated as malignancies based on frozen sections. A meta-analysis for Hürthle cell lesions in thyroid FNA in nine institutions from six Asian countries revealed that there was interinstitutional variation in the cytologic interpretation of Hürthle cell morphology and in Bethesda categorization [33]. Hürthle cell-rich aspirates were most frequently categorized as AUS/FLUS, followed by FN/SFN.…”