Fine Needle Aspiration Cytology in the Diagnosis and Management of Thyroid Diseases

Background: Swellings of thyroid are frequently encountered in surgical practice. With clinical evaluation it is difficult to distinguish early malignant lesions from common benign goiters. Surgical excision is the only means by which a definitive diagnosis is obtained based on HPE. An alternative approach is called for other than surgery as most cases are benign. FNAC is a simpler and safer procedure carried out in the OPD with minimal equipment and has good patient compliance. The present study aims at correlating the cytological diagnosis with the final histological diagnosis to evaluate the sensitivity, specificity and accuracy of FNAC smears, thereby its role in preoperative diagnosis in planning proper management. Aim: To determine the accuracy and the role of fine needle aspiration cytology (FNAC) as a diagnostic modality in the diagnosis and treatment of thyroid diseases. Materials and methods: A proforma was drafted for the study of all patients presenting with history of palpable thyroid swelling and undergo surgery in our hospital. Clinical presentations, FNAC and histopathology of all cases were documented. Results: 100 cases who presented with thyroid swellings were studied and their histopathological diagnosis was compared with the FNAC. Of the 86 cases which were seen benign by FNAC, 82 were confirmed by histopathology. Of the 18 cases which were proved to be malignant by histopathology 14 were only seen as malignant by FNAC. The sensitivity of FNAC in the diagnosis of benign lesions was found to be 77.78%, specificity was 100%, positive predictive value 100% and accuracy is 96%. Conclusion: Most of our patients were between third and fourth decade, with females being predominant. Most cases were benign of which multinodular goiter being the most dominant pathology (25%). Among the malignancies, majority being papillary carcinoma (78.94%). The sensitivity, specificity and predictive value of positive smears being 77.78%, 100%, and 100% respectively. FNAC was of greater help in the preoperative management of thyroid swellings. Multinodular goiters and colloid goiters were distinguished easily by FNAC but confusion prevailed in cases of follicular adenomas. In patients who cannot be followed up regularly clinical suspicion should be one of the indications for surgery despite of FNAC being negative. FNAC is simpler, safer, quicker and more informative, when compared with other sophisticated methods in the diagnosis of thyroid lesions.