RECLASSIFICATION OF THYROID LESIONS BASED ON THE BETHESDA SYSTEM BY FINE NEEDLE ASPIRATION CYTOLOGY: A 2 YEAR STUDY FROM A TERTIARY CARE CENTRE IN NORTH-EAST INDIA

Abstract

Background: Thyroid gland is affected by a vast array of disorders like developmental, inflammatory, hyperplastic and neoplastic disorders. Both non-neoplastic and neoplastic diseases affect it and led to diffuse or nodular enlargement. FNAC is widely considered as the diagnostic technique of choice in the assessment of thyroid lesions. In the Bethesda system for reporting thyroid cytopathology (TBSRTC), the six diagnostic categories have been designated one to six roman numbers. A thyroid FNA specimen is considered to be satisfactory for evaluation (and benign), at least 6 groups of benign follicular cells are required, and each group composed of at least 10 cells.

Methods: A two year retrospective cross sectional study was conducted. Patients attending cytology out-patient department, were the study population. Consent was obtained from all the patients before the start of the procedure. Twenty ml syringe with 24 gauge needle fitted in Cameco handle was used for aspiration. Prepared smears were stained with Giemsa stain. Any cystic fluid thus withdrawn from the swelling was centrifuged and the deposit was studied microscopically after spreading.

Results: A total of 539 thyroid swelling were aspirated during the study period. Of 539 cases 88% of cases were reported in females and 12% of cases were reported in males. Ninety percentage of cases were reported under benign category. Twenty five(4.6%) cases were reported as malignant during the study period, out of which 23(4.2%) cases were reported as papillary carcinoma. Papillary carcinoma constitutes the most common malignant lesion reported during the study period.

Conclusion: The Bethesda system provides a standardized nomenclature for thyroid cytopathology reporting with improved interobserver reproducibility. Facilitates better understanding between cytopathologist and clinicians for uniform and proper management.

Key words: Thyroid, Fine needle aspiration cytology (FNAC), The Bethesda system.