Accuracy Of Fine Needle Aspiration Cytology In Diagnosis Of Thyroid Swellings

Introduction : Fine needle aspiration cytology is regarded as the gold standard investigation in diagnosis of thyroid swellings. Published data suggest an overall accuracy rate of 75%1 in the detection of thyroid malignancy. The aim of this study was to determine the accuracy of FNA cytology in detection of thyroid malignancy in our surgical unit. Methods : Between1989-2002, 144 patients who underwent thyroid resection by single consultant surgeon and who had preoperative FNA were enrolled in this retrospective study. The preoperative FNA results were compared with definitive histological diagnosis following thyroid resection. Fine needle aspiration cytology was performed using aspirate and non-aspirate techniques on each thyroid swelling. The cytological sample was assessed by a single consultant pathologist and was classified as inadequate, non-neoplastic, neoplastic, suspicious or indeterminate. The histology were classified as non-neoplastic (benign), neoplastic (malignant). Results: Fine needle aspiration cytology analysis revealed 94(13.88%) non-neoplastic, 6(65.27%) neoplastic and 20(4.16%) suspicious aspirates. Twenty (13.88%) samples were inadequate and 4(2.77%) samples were indeterminate. Histological analysis showed 118(81.94%) benign, 26(18.05%) malignant specimens. Fine needle aspiration cytology had a sensitivity, specificity and accuracy rate of 52.6%, 86.6%, and 79.1% respectively for diagnosing thyroid malignancy. Conclusion: The results are comparable with the current published data and demonstrate that FNA cytology in our hands is accurate investigation for preoperative diagnosis for the detection of thyroid malignancy.