FNAC accuracy in diagnosis of thyroid neoplasms considering all diagnostic categories of the Bethesda reporting system: A single-institute experience

Abstract

Background:Thyroid fine-needle aspiration cytology (FNAC) is a valuable test used for diagnosing diseases of the thyroid gland.Aims:Using all satisfactory categories of the Bethesda system, this study aimed to determine the accuracy with which FNAC diagnoses thyroid neoplasms. We also discuss the factors that affect diagnosis accuracy.Settings and Design:A comparison was drawn between FNAC results and final histological diagnosis using samples collected over a period of 3 years.Materials and Methods:For all patients, age, sex, cytological features, and histological types were determined. All cases of false negative (FN) and false positive (FP) diagnosis were reanalyzed.Statistical Analysis Used:The chi-square test and univariate analysis were performed to examine the relationship between different variables.Results:About 52% of the cases were found malignant, and they were of six different histological types. Papillary carcinoma was the commonest type of malignancy at 76.9%. The rate of malignancy was 63% in males and 49.4% in females. In two of the FN cases, the tumor had a diameter of ≥35 mm. Of the 12 FP cases, nine were in the follicular neoplasm or suspicious for follicular neoplasm Bethesda category. FNAC diagnosis had 95.2% sensitivity, 68.4% specificity, 83.3% positive predictive value, 89.6% negative predictive value, and 85.14% accuracy.Conclusions:FNAC was found to have a high level of sensitivity and an acceptable degree of specificity in diagnosing different types of thyroid neoplasms. The presence of microfollicular structures or crowded cellular clusters is a challenge to diagnosis, particularly in low-quality specimens.

Bethesda System for Reporting Thyroid Cytopathology: A three-year study at a tertiary care referral center in Saudi Arabia

“…Therefore, the objective of the current study is to stratify the risk of malignancy in the thyroid nodules based on the Bethesda system, which enhances the interpretation of the FNAC reports and enables a more accurate study and diagnosis of such thyroid nodules[13,15]. In this study, the distribution of age and gender among the patients is almost similar to those recorded in identical studies[1,2,16]. Besides, the female/male ratio reported in this study for thyroid cancer (4.7:1) concurs with the concept that thyroid cancer occurs more commonly among women.…”

“…While the majority of the nodules are benign (non-cancerous), they are normally the first indicators of thyroid cancer; therefore, further investigations are required to identify the cancerous nodule[1,2]. …”

Accuracy of Fnac in Diagnosing Thyroid Nodules: A Single Institution Experience

“…The importance of thyroid nodules lies in the fact that although most nodules are benign, they may be the first sign of malignancy [6]. In the evaluation of patients with thyroid nodules, FNA has been accepted world over as the first-line screening test.…”

“…This is due to the fact that the nuclear changes of papillary carcinoma may be slight or focal, and also because features such as nuclear groove may be seen in other lesions, particularly in low-cellular smears [14]. Minimal cellularity of FNA specimens may lead to an erroneous diagnosis of nodular goiter in a case that is actually a papillary carcinoma [6]. This has management implications because an FNA diagnosis of follicular neoplasm or malignancy will necessitate surgery where as a benign lesion by FNA can be managed conservatively [7].…”

“…Thyroid follicular cells in chronic lymphocytic thyroiditis may show a mild to moderate degree of cellular atypia or hurtle cell metaplasia leading to erroneous diagnosis of Hurthle cell/follicular neoplasm [6].…”