Diagnostic accuracy of fine needle aspiration cytology of thyroid and evaluation of discordant cases

Abstract

In spite of high accuracy of FNAC in differentiating between a benign and malignant lesion, certain pitfalls should be kept in mind. The common false negative diagnoses were follicular pattern cases which constitute a 'gray zone', cystic papillary thyroid carcinoma (PTC) and papillary microcarcinoma. The reason for false positive diagnoses was the occurrence of nuclear features characteristic of PTC in other thyroid lesions. Awareness of pathologist regarding these pitfalls can minimize false negative/positive diagnoses.

TBSRTC in LBC Preparation of Thyroid Lesions– Preferred over the Conventional Cytology

“…In the present study the sensitivity to diagnose malignancy was 87.17% and the specificity was 99.52%. This result is comparable to other studies [8,10,12,13,14,15,16] and agrees with the study by Sharma C. The PPV was 87.17% & accuracy in our study was 97.6% and it is closest to the study by Aravinthan T et al [10] .…”

“…The most common cause of false negative error is inadequate or improper sampling. The false positive rate (FPR) in the present study was 0.48% in CP and 0.91% in LBC which was lower than most of the studies [4,8,10,11,13] and was comparable to the study of Guhamallick et al [8] and Sharma C [12] . False negative rate (FNR) in our study was 12.83% in CP and 14.71% in LBC, which was higher than most of the studies and was comparable to the study by Sharma C [12] .…”

Thyroid cytology—nuclear versus architectural atypia within the “Atypia of undetermined significance/follicular lesion of undetermined significance” Bethesda category have significantly different rates of malignancy

“…The technique of FNAC was first introduced in Scandinavia in the 1950s and gained worldwide popularity in the 1980s . Over the years, it has gained significance as a quick, safe and relatively simple method to differentiate malignant from benign thyroid nodules.…”

“…The technique of FNAC was first introduced in Scandinavia in the 1950s and gained worldwide popularity in the 1980s. 3 Over the years, it has gained significance as a quick, safe and relatively simple method to differentiate malignant from benign thyroid nodules. It is also minimally invasive; 4 cost effective; 5 and, at the same time, highly reliable, with an accuracy rate as high as 97%; 3 thus, it is regarded as the gold-standard first-line diagnostic test in the evaluation of thyroid nodules.…”

“…3 Over the years, it has gained significance as a quick, safe and relatively simple method to differentiate malignant from benign thyroid nodules. It is also minimally invasive; 4 cost effective; 5 and, at the same time, highly reliable, with an accuracy rate as high as 97%; 3 thus, it is regarded as the gold-standard first-line diagnostic test in the evaluation of thyroid nodules. 6 The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was proposed in 2007 and classifies results into 6 diagnostic categories, each with a suggested risk of malignancy and specific recommendations for subsequent management.…”