The Bethesda System for Reporting Thyroid Fine-Needle Aspiration Cytology: A Kuwaiti Experience - A Cytohistopathological Study of 374 Cases.

INTRODUCTION: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) identifies 6 diagnostic categories in which the risk of malignancy increases respectively. The aim of our study was to assess TBSRTC reporting in our hospital and to evaluate its specificity based on cytohistological correlation. METHODS: A histological diagnosis was available in 374 (110 males and 264 females) out of 7,809 thyroid aspirates examined at Mubarak Al-Kabeer Hospital, Kuwait, from 2004 to 2012. The aspirates were classified in accordance with TBSRTC. RESULTS: Thyroid aspirates were classified as nondiagnostic (n = 18; 4.8%), benign (n = 114; 30.5%); atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS; n = 59; 15.8%), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN; n = 17; 4.5%), suspicious for malignancy (SM; n = 80; 21.4%), or malignant (n = 86; 23.0%). In 75 of 86 malignant cases, a papillary carcinoma was detected. There were 3 (1.6%) false-positive aspirates and the sensitivity, specificity, negative predictive value, and positive predictive value were 91.0, 61.9, 84.2, and 75.3%, respectively. CONCLUSIONS: Our results are fairly comparable to those of various previous studies in the SM, AUS/FLUS, and SFN categories. The higher rates observed in the nondiagnostic and benign categories were possibly due to limited guided aspirations and a lack of on-site evaluation for all cases.