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International Journal of Recent Trends in Science and Technology, ISSN 2277-2812 E-ISSN: 2249-8109
Volume 16, Issue 2, Sept 2015 pp 332-338
Cyto-histological correlation of thyroid lesions– experience at a tertiary care hospital
N Priyathersini1, G Kanimozhi2, S Rajendiran3
1,2Assistant Professor, 3Professor, Department of Pathology, Sri Ramachandra Medical College and Research Institute, Porur, Chennai-600116, Tamil Nadu, INDIA.
Introduction: Fine needle aspiration cytology (FNAC) is the commonly used test for thyroid nodules. FNAC is a cost effective procedure. Based on the cytology findings patients can be managed conservatively or subjected to surgery. Objectives: The aim of our study was to find the diagnostic accuracy of FNAC in thyroid lesions, compare it with histopathology and analyze the causes for discordance. Materials and Methods: A retrospective hospital- based study was conducted in our Department of Pathology. Data were collected from the records of FNAC and histopathology of thyroid lesions from January 2010 to June 2013. Results: FNAC was done on 1137 patients. Among them, 70 aspirates (6.16%) were sub optimal for definitive opinion. The thyroid lesions were categorized based on Bethesda system. The most common thyroid lesions were under Bethesda category II with 928 cases (81.6%).There were 14 cases (1.2%) in Bethesda III, 40 cases (3.5%) in Bethesda IV, 45 cases (5%) in Bethesda V and 40 cases (3.5%) in Bethesda VI category. The Bethesda category II lesions included nodular colloid goiter/ colloid nodule (38.79%), adenomatous nodule (15.39%), thyroiditis (21.81%), cystic lesion of thyroid (2.37%), and benign thyroid lesions (2.46%) The malignant lesions (3.5%) included papillary thyroid carcinoma and anaplastic carcinoma. Histopathology was available for 103 (9%) cases. Among them 72 benign lesions, 59 cases correlated with the excision biopsy findings. In 10 malignant lesions 8 correlated and in the 3 suspicious cases 2 of them were found to be malignant. The cytological discrepancy was noted in 16 cases (18.8%..%) and the false positive was in 3cases (3.5%) whereas the false negative was 13 (15.3%) The discordant cases were reviewed and the discrepancies in diagnosis were grouped under three categories as sampling error (47%), interpretation (40%) error and nature of lesion (13%). Conclusions: FNAC is a highly reliable method for the diagnosis of thyroid lesions. The discrepancies can be overcome by extensive sampling and strict adherence to the minimum set of criteria for diagnosis.