Cytomorphological Spectrum of Thyroid Lesions Based on Bethesda Reporting System: Diagnostic Utility and Pitfalls

Abstract

Introduction: Fine Needle Aspiration Cytology (FNAC) is the frontline diagnostic tool in assessing Thyroid enlargement. FNAC is simple, easy to perform, cost effective procedure with rapid diagnosis. Other diagnostic tests like Ultrasound, radionucleotide scanning, Thyroid profile are adjuvant to FNAC which is more reliable. Aim: To categorise the spectrum of Thyroid lesions on FNAC according to the Bethesda system for Reporting Thyroid Cytopathology (TBSRTC) and study its utility and pitfalls. Materials and Methods: This was a retrospective observational study carried out in the Department of Pathology at Government Medical College/Government General Hospital, Mahabubnagar, Telangana, India, from January 2019 to December 2021. The analysis of the data was done from January 2022 to June 2022. FNAC and fine needling was performed in cases of enlarged Thyroid gland, the smears were prepared and fixed in 95% ethyl alcohol, stained with Hematoxylin and Eosin and Papanicolaou stain. Cytohistopathological concordance was done wherever was possible. Sensitivity, Specificity, Positive Predictive value, Negative Predictive value were calculated. Results: Out of 155 cytology cases, 8 cases (5.16%) were unsatisfactory/nondiagnostic, 133 cases (85.80%) were Benign lesions, 8 cases (5.16%) were follicular neoplasm/ suspicious for follicular neoplasm, No cases were reported as Atypia of undetermined significance, 3 cases (1.93%) were suspicious for malignancy and 3 cases (1.93%) were malignant. Cytohistopathological concordance was studied in 19 cases. One of the case reported on cytology as Anaplastic carcinoma was referred to higher center for further management. Conclusions: FNAC plays a pivotal role in diagnosis of Thyroid Swellings. The Bethesda system for reporting Thyroid Cytopathology effectively categorises the Thyroid lesions into various sub groups which facilitates better communication between the pathologist and clinician resulting in proper management of the patient. In this study, the number of Benign cases predominated and occurred in females. Cases presenting with nodular lesions, suspicious for malignancy and malignant lesions are advised surgical resection for further evaluation. The Bethesda system was found useful in categorisation of lesions and in advising medical or surgical management, urgency of treatment and the extent of surgery.

Keywords

• bethesda system for thyroid cytology
• cytohistological concordance
• fine-needle aspiration cytology