The cytologic category of oncocytic (Hurthle) cell neoplasm mostly includes low-risk lesions at histology: an institutional experience

Abstract

Design: The cytological diagnosis of oncocytic/Hurthle cell neoplasms (OCN) represents a challenge with which cytopathologists face up to in their practice. The majority of these lesions undergo surgery for a definitive characterization of the nature mainly due to their more aggressive behavior than other malignant follicular lesions. In this study, we aimed at the evaluation of the effective malignant rate in a large cohort of OCNs. Methods: From January 2008 to December 2011, we analyzed 150 cyto-histological OCNs and 64 benign oncocytic/Hurthle lesions (BOL). Both groups of patients were analyzed for clinical and cytohistological parameters. All the nodules were sampled under sonographic guidance and processed with the liquid-based cytological method. Results: In agreement with literature, we found a significant correlation only with female gender in both OCN (PZ0.0160) and BOL groups. The 64 BOLs were histologically diagnosed as 15 Hashimoto thyroiditis (HT), 45 hyperplastic nodules in HT, and four papillary thyroid carcinomas (PTC, 6.2%). The 150 OCNs resulted in 141 (94%) oncocytic adenomas and nine (6%) malignant lesions. The latter group included five oncocytic carcinomas (OCC), three oncocytic variants of PTC, and one macrofollicular PTC featured by mild nuclear clearing with a dispersive cellular pattern. The malignant rate was respectively 6.2% in BOLs without any OCC whereas 3.3% OCC diagnosed in the OCN category. Conclusions: Our OCNs mostly resulted in histological adenomas with a lower rate of malignancy than in other series. Some morphological parameters (nuclear clearing, dysplasia, and dispersive cellular pattern) might be helpful in stratifying OCN patients into different risks of malignancy.

Thyroid “Atypia of undetermined significance” with nuclear atypia has high rates of malignancy and BRAF mutation

“…By comparing both calculated malignancy rates, the AUS‐NA subcategory revealed a substantially higher rate of malignancy (40.7% of FNA cases; 97.1% of resected cases) than what has been previously reported for the AUS category, or those found in other AUS subcategories, especially AUS‐MF (4.8% of FNA cases; 22.2% of resected cases) and AUS‐HC (5% of FNA cases; 20% of resected cases). Recently, Rossi et al reported that oncocytic/Hürthle cell features on FNAC showed a low risk of malignancy, supporting the low malignancy rate in the AUS‐HC subcategory in this study . These findings can be partly explained by the fact that the relatively large number of cases were histologically confirmed in the subcategory of AUS‐NA (n=68, 31.5%) as compared with the subcategories of AUS‐MF and AUS‐HC (n=9, 20.9%; n=4, 20.0%, respectively).…”

“…Recently, Rossi et al reported that oncocytic/ H€ urthle cell features on FNAC showed a low risk of malignancy, supporting the low malignancy rate in the AUS-HC subcategory in this study. 21 These findings can be partly explained by the fact that the relatively large number of cases were histologically confirmed in the subcategory of AUS-NA (n568, 31.5%) as compared with the subcategories of AUS-MF and AUS-HC (n59, 20.9%; n54, 20.0%, respectively). Moreover, in Korea, PTCs comprise approximately 95% of thyroid cancer and 90% of PTCs are of classic type, whereas follicular carcinomas are very rare.…”

Preoperative Diagnosis of Neoplastic or Malignant Hürthle Cell Lesions: A Chimera?

“…Reported malignancy rates for HC lesions diagnosed by FNAC vary between 5 and 45% [3, 5, 9, 17]. In the meta-analysis by Straccia et al [18], HC lesions categorized as FN/SFN resulted more frequently in benign lesions on histology (65%), and the rate of malignancy ranged between 14 and 70%.…”

Follicular nodules (Thy3) of the thyroid: is total thyroidectomy the best option?

“…The sonographic features of thyroid nodules have consistently failed to predict malignancy in FN with indeterminate cytology [13,14,22]. However, a hypoechoic appearance, the presence of microcalcifications (defined as < 2 mm hyperechoic spots), irregular or blurred margins, and intra-nodular vascularization are all taken as potential markers of malignancy, especially when present in combination [5,11,21].…”