Aim: To consider the clinical impact of introducing the Bethesda System of Reporting Thyroid Cytopathology (BSRTC) to a dedicated thyroid cytology clinic run by a single endocrinologist.

Methods: FNA episodes between 2006-2011 were identified from the archived records and those with corresponding histology were correlated.  The FNA reports were reviewed and reclassified using the guidelines published in the BSRTC atlas with particular emphasis on the atypical category.  HAPS currently uses a 5 tier reporting system compared with the BSRTC 6 tier system with the main difference being the atypical categaory is separated into both atypia of undetermined significance (AUS) and follicular lesion (FN) in BSRTC and in the management of the non-diagnostic category.  Potential clinical implications were inferred from the different classifications.

Results: 1122 FNAs were performed on 985 patients (age range 10-86yo).  245 histology samples were available for correlation.  This included 84/93 atypical cases, 21/21 suspicious for malignancy and 15/19 malignant FNAs. 71/84 (84%) atypical cytologies resulted in neoplastic lesions, including 43 reclassified BSRTC III cases (72%) which would undergo repeat FNA if BSRTC management guidelines were followed.  2/42 (5%) of our non-diagnostic FNAs warranted repeat FNA, whereas BSRTC recommends repeat FNA on all non-diagnostic cases unless clinically indicated otherwise.

Conclusion:  Applying BSRTC to our cases would have resulted in 95% of non-diagnostic cases unjustifiably being repeated and 72% of BSRTC III cases undergoing repeat FNA with potential delay in diagnosis. The atypical cases are the subject of a review and reclassification program. The conversion to BSRTC reporting must be informed by the above data.