Correlation of fine needle aspiration cytology with histopathology for thyroid swellings in a tertiary care hospital in South India
Chirag Pereira, Rohan Dsouza, Leo F. Tauro
Father Muller Medical College
chiggy1989@gmail.com
Keywords: щитовидная железа, тонкоигольная аспирационная цитология, карцинома щитовидной железы, папиллярная карцинома, категория Bethesda, thyroid, FNAC, thyroid carcinoma, papillary carcinoma, Bethesda category
Abstract
Fine needle aspiration
cytology (FNAC) is documented to be a good tool in the diagnosis of
thyroid lesions. It has good diagnostic accuracy and is an inexpensive
investigation. Although a good instrument it does have its own
limitations especially when it comes to distinguishing a follicular
adenoma from follicular carcinoma thyroid. Objectives of the study was
the evaluation of FNAC in the diagnosis of thyroid lesions by
determining its sensitivity, specificity, diagnostic accuracy, positive
predictive value and negative predictive value. Material and methods.
This is a retrospective study of 580 cases of thyroid swelling admitted
to our hospital and undergone thyroidectomy over a period of 5 years
from 2015 to 2020. After thyroidectomy, FNAC reports (Bethesda system
for reporting) of those patients were collected and were compared and
analyzed with the histopathology reports. Category 1 and category 3
cases were excluded from calculation due to uncertainty in reporting.
Data were analyzed to calculate the sensitivity, specificity, diagnostic
accuracy, positive predictive value and negative predictive value of
FNAC. Results. Our study included a total of 580 cases of thyroid
swellings. The male to female ratio was 1:18.2 and the median age was 43
years. On FNAC, 428 cases (73.7 %) were benign, 35 cases (6 %) were
indeterminate, 39 cases (6.7 %) were follicular neoplasm, 30 cases (5.1
%) were suspicious for malignancy and 34 (5.8 %) were malignant. 14 (2.4
%) cases were unsatisfactory. Cytology report was then compared with
histopathological reports. FNAC had a sensitivity of 84.2 %, specificity
of 97.2 % and a diagnostic accuracy of 94.5 %. The positive predictive
value and negative predictive value were 88.3 and 96 % respectively.
Conclusions. FNAC is a more specific than sensitive when distinguishing
between benign and malignant lesions of thyroid. It has good diagnostic
accuracy and hence should be used in all tertiary care hospitals prior
to surgery in diagnosing thyroid lesions.
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