A histological assessment of the Bethesda system for reporting thyroid cytopathology (2010) abnormal categories: a series of 219 consecutive cases

Abstract

OBJECTIVE: The purposes of this study were to establish the distribution of thyroid lesions that were seen in Hatay (a province of southern Turkey), to review the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of thyroid nodules and to correlate the FNAC results with the histopathology of the excised specimens, especially in indeterminate cases. METHODS: Data on patient cytology were retrieved by a retrospective search of all thyroid FNAC specimens that had been evaluated at the Department of Pathology, Antakya Public Hospital, Hatay, Turkey between January 2009 and February 2011; 1021 thyroid FNAC samples were reviewed and interpretations were recorded according to the Bethesda system for reporting thyroid cytopathology (TBSRTC). The results of adequate FNAC samples were compared with the histological diagnoses in the cases in which surgery was performed, and the malignancy rates, especially in indeterminate categories, were calculated. RESULTS: Of the 1021 FNAC samples, 697 (68.3%) were benign, 122 (11.9%) were non-diagnostic, 100 (9.8%) were atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 41 (4%) were follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 36 (3.5%) were suspicious for malignancy (SM) and 25 (2.4%) were malignant. In 219 cases, there was follow-up histology. Rates of malignancy were as follows: benign, 0%; AUS/FLUS, 12.7%; FN/SFN, 35.0%; SM, 91.4%; malignant, 100%. CONCLUSIONS: In our study, the cytohistological correlation of benign and malignant lesions was 100%. In the indeterminate categories, we recommend that clinicians should evaluate both the clinical and radiological findings of patients in addition to the FNAC results.