Correlation between thyroid fine needle aspiration cytology and
post-operative histology: A 10-year single-centre 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.
Keywords: Fine needle biopsy; thyroid cytology; thyroid cancer;
diagnostic accuracy