1Assistant Professor, Dept. of Pathology, Father Muller Medical College, Mangalore, Karnataka
2Resident, Dept. of Pathology, Father Muller Medical College, Mangalore, Karnataka
To evaluate the application of The Bethesda System of Reporting of Thyroid Cytopathology (TBSRTC) in a non-referral setting of a teaching hospital.
We included consecutive thyroid FNAs performed in our institute for a period of two years. The FNAs were classified into six general diagnostic categories (DCs) as per TBSRTC. Analysis was done by calculating the sensitivity, specificity, negative and positive predictive values, likelihood ratios and the incidence of malignancy in each of the categories with respect to the histopathologic diagnosis obtained after surgical resection.
A total of 1270 FNAs were categorized as per TBSRTC. DC I constituted 15.6% of cases, DC II-74.3%, DC III-3.8%, DC IV-2.4%, DC V-1.% and DC VI-3.1% of cases. Histopathological follow up was available for 253 cases(19.9%)The incidence of malignancy was 0%in DC I, 2.6% in DC II, 33.3% in DC III, 46.15% in DC IV, 77.8% in DC V and 100% in DC VI. The positive predictive value for DC IV, V and VI was 79%and negative predictive value for DC II lesions was 97.2%. A repeat FNA without sonological guidance could re-categorize 22 of the 38 DC I patients into DC II.
The TBRTC is a valid method of reporting thyroid FNAs in a non-referral setting as evidenced by the increasing incidence of malignancy obtained with higher DCs.
The Bethesda System, Thyroid Cytopathology, Histopathologic evaluation, Diagnostic category, Malignancy
