Correlation between thyroid fine needle aspiration cytology and
post-operative histology: A 10-year experience
Abstract
Introduction Fine needle aspiration cytology (FNAC) forms part of the
routine workup for suspicious thyroid nodule. Whilst cytological
analysis is less precise than histological assessment, it is quick and
easy to perform and may avoid the need for invasive and potentially
risky surgery. Methods This retrospective study spanning a 10-year
period compared pre-operative FNAC with post-operative histology results
to establish the accuracy of diagnosis and malignancy rates within our
population. These results were then compared to the published figures in
the literature. Results The histological reports of 659 consecutive
cases of thyroid surgery between 2006 and 2015 were retrieved from our
hospital’s database. Among the 471 patients (71.5%) who underwent
preoperative FNAC, the postoperative histology was reported as benign in
352 (74.7%) and malignant in 119 cases (25.3%). PTC was the commonest
histological diagnosis. Thy1 grade was reported in 165 (30%) cases,
with 19.4% had a final histological diagnosis of malignancy. 85.3% of
patients in the Thy2 group had a benign final histological diagnosis,
while 14.7% had malignancy (false negative results). Malignancy was
found in 89% of Thy4 and 100% of Thy5 group patients. Conclusions
Rates of malignancy varied considerably from those in the published
literature. Each centre should be able to quote a local malignancy rate
during patient counselling. It is also prudent for all units performing
thyroid diagnostics to investigate the factors that might lead to
inaccuracies in reporting.