Vol. 7, Issue 2, Part A (2025)

Introduction: Fine-needle aspiration cytology is recommended as the first and most decisive diagnostic step in the workup of patients with thyroid swelling. Thyroid swelling is a common clinical presentation in ENT practice and it carries significant morbidity and even mortality if not managed properly. They are endemic in mountainous region of the world, where the soil, water & food supply contain little iodine. Fine Needle Aspiration Cytology (FNAC) is important for pre-operative and pre-treatment diagnosis of benign and malignant thyroid lesions, thus decreasing the incidence of unwanted surgeries.
Objectives: To find out the Correlation of FNAC with postoperative histopathology in diagnosis of thyroid nodule.
Methods: A cross-sectional observational study was carried out in the Department of ENT and Head Neck-Surgery, Dhaka Medical College Hospital, Dhaka, Bangladesh from December 2021 to May 2023. Patients with thyroid swelling were included from the study. Sampling technique was purposive sampling. Detail history was taken. Thorough ENT examination and related systemic examinations were done. Diagnosis of thyroid nodule was confirmed by ultrasonography of thyroid. Prior to surgery relevant investigations were done and informed written consent were taken from all patients. Each patient was assessed before surgery by FNAC and post operatively by histopathology. 
Results: In the present study, age of the patients ranged from 10 to 70 years. The highest number of patients (39.3%) were in the 31-40 years of age group, followed by 16 (26.2%) in the 41-50 years age group. Mean age of study subjects was 37.5±8.2 year. In our study most of the respondents were female. Pie chart showing that 51(83.61%) of the respondents were female and 10(19.39%) were male. In the present study, USG guided FNAC of thyroid lesion result was interpreted as per Bethesda system. Most of the respondents was diagnosed as Bethesda class II in USG guided FNAC. In our study Bethesda Class II Benign (38/61, 62.2%), class III Follicular Neoplasm or Suspicious for a Follicular Neoplasm (5/61, 8.19%), class IV Atypia of Undetermined Significance or Follicular lesion of Undetermined Significance (8/61, 13.1%), class V Suspicious for Malignancy (7/61, 11.4%) and class VI Malignant (3/61, 4.91%). Histopathology findings revealed that among 61 patients, benign lesion was 42(68.9%). Malignant causes were 19(31.1%). The p-value is 0.021. This result is significant at p<.05. So FNAC finding is significant in evaluation of thyroid swelling. There were 6 false positive cases from correct diagnosis and only 2 smears were false negative when compared with histopathology biopsy. True positive was 17 cases & true negatives was 36 cases. Pearson’s correlation coefficient was 0.85 which is very strong for positive relationship.
Conclusions: It is important to recognize the range of malignancy among thyroid swelling in this region because of different treatment modality and emotional burden on the patient. FNAC greatly facilitates the precise and adequate sampling of tissues from thyroid lesions thus enabling an accurate diagnosis. This may lead to the elimination of potential morbidity of unnecessary surgery. Ultrasound guidance helps in the selection of the most suspicious focus within the nodule especially with a background of multi-nodularity. It has very strong positive relationship with post-operative histopathology.