[400] Fine-Needle Aspiration of Hurthle Cell Lesions: A 10-Year Retrospective Study of 147 Cases

Susan W McKee, Howard H Wu, Xiaoyan Wang, Harvey M Cramer, Shaoxiang Chen. Indiana University School of Medicine, Indianapolis, IN

Background: Hurthle cell change is not an uncommon finding in thyroid fine-needle aspiration (FNA) cytology, and can be associated with various non-neoplastic conditions as well as follicular neoplasms and thyroid carcinoma. Diagnostic challenges arise when attempting to classify Hurthle cell change as metaplastic or as suggestive or diagnostic of a Hurthle cell neoplasm.
Design: A computerized search of our laboratory information system was performed for the 10-year period from August 2002 through August 2012 to identify all thyroid FNA and correlating surgical pathology diagnoses that included Hurthle cell or oncocytic nomenclature. Those cases that did not have corresponding thyroidectomies after FNA were excluded. Based on the follow-up diagnosis, the risk of malignancy was calculated, after excluding cases of papillary microcarcinoma (PMC). The risk of neoplasm was calculated, including all malignancies, PMC and adenomas.
Results: A total of 147 FNA, thyroidectomy specimens and clinical histories were analyzed over a 10-year period. The patient ages ranged from 16 to 83 years, with a mean of 52. The female to male ratio was 3.9:1. The size of the lesions aspirated ranged from 0.2 cm to 9.0 cm. The FNA diagnoses were classified as follows: benign (12 cases, 8%), atypia of undetermined significance, cannot exclude Hurthle cell neoplasm (AUS-HCN) (56 cases, 38%), Hurthle cell neoplasm (HCN) (72 cases, 49%), suspicious for malignancy (5 cases, 3%), malignant (1 cases) and nondiagnostic (1 case). Of the 12 cases diagnosed as benign by FNA, 5 were adenomas, 5 were benign non-neoplastic (BNN), and 2 were follicular carcinomas. Of the HCN cases, follow-ups showed 31 adenomas, 15 BNN, 21 malignant and 5 PMC. Of the AUS-HCN cases, histology demonstrated 19 adenomas, 22 BNN, 7 malignant and 8 PMC. Those 5 FNAs classified as suspicious for malignancy yielded 1 adenoma, 1 BNN and 3 malignancies. The one malignant FNA was an oncocytic variant of papillary carcinoma. An adenoma was identified on histologic follow-up of the one nondiagnostic FNA.
Conclusions: The risks of malignancy and of neoplasm were 13% and 61% for AUS-HCN and 29% and 79 % for HCN, respectively. The risk of malignancy is within the 5-15% suggested for AUS and 15-30% suggested for follicular neoplasm, as described in the Bethesda System for Reporting Thyroid Cytopathology. One of the false negative cases was due to interpretation error and, in retrospect, should have been diagnosed as "AUS-HCN". The other false-negative case was an outside consultation and the cytologic smears were not available for review.
Category: Cytopathology

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 93, Tuesday Afternoon


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