ANALYSIS OF FINE NEEDLE ASPIRATIONS OF THE THYROID: CYTOLOGICAL-HISTOPATHOLOGICAL CORRELATION AND OUTCOMES OF THE BETHESDA SYSTEM
Abstract
Objective
The Bethesda system is widely used to evaluate
aspiration of thyroid nodules. The aim of the study is to
evaluate the usability of the system by the correlation
between cytology and final histopathology results and
to review the literature.
Materials and Methods
Fine needle aspiration of thyroid nodules reported using
Bethesda system were analyzed. Malignancy rates
were calculated by the results of thyroidectomies. To
analyze the power of the Bethesda system six distinct
subgroups were designed. The sensitivity, specificity,
positive predictive value, negative predictive value
and diagnostic accuracy were calculated separately
in these subgroups. The data were analyzed using
SPSS 20 for Windows.
Results
The distribution of thyroid nodules according to
the Bethesda was 2212 (33.5%), 3163 (47.9%),
720 (10.9%), 67 (1%), 361 (5.5%) and 75 (1.1%),
respectively. Of 873 nodules that underwent
thyroidectomy, 254 (29.9%) were diagnosed as
malignant. The diagnostic categories according to
thyroidectomies were 233 (26.7 %), 277 (31.7%),
137 (15.7%), 23 (2.6%), 163 (18.7%) and 40 (4.6%),
respectively. The malignancy rates of each Bethesda
category were 14.5%, 6.8%, 32.8%, 52.1%, 66.8%
and 97.5%. The sensitivity, spesifity, positive
predictive value (PPV), negative predictive value
(NPV) and accuracy of fine needle aspiration was
calculated and ranged from 61.8% to 89.3%, 79.6% to
99.6%, 70.4% to 97.5%, 84.5% to 93.1% and 79.5%
to 93.6%, respectively.
Conclusion
The limitation of this study is that the B1 category is very
high. However, since the data are evaluated by only
one pathologist and it is one of the first three studies
with the highest number of cases, it makes a significant
contribution to the literature in terms of all categories
except B1. The Bethesda system is a classification
that provides the clinician with appropriate clinical
follow-up and the accurate treatment approach, and a
high interobserver agreement for pathologists.