Role of fine-needle aspiration cytology & ultrasound in the management of solitary thyroid nodule

Objectives To evaluate the effectiveness of fine-needle aspiration cytology (FNAC) & ultrasound scanning (US) in the diagnosis and management of solitary thyroid nodules. Materials & Methods A retrospective study was carried out on 63 patients who were euthyroid and had a clinically palpable solitary thyroid nodule, who underwent either total or hemi-thyroidectomy, during a period of two years (January 2018 to December 2019) in the ENT unit of a tertiary care hospital in Sri Lanka. All patients with FNAC of Bethesda ≥5 underwent total thyroidectomy. Diagnostic hemi-thyroidectomy was performed only in patients with a FNAC of Bethesda ≤4, irrespective of US suspicious features. Results Mean age was 46.9 years (±13.2). 53(84.1%) patients were females and 10 (15.9%) of them were male. 28(44.4%) patients had histologically proven malignancy while the other 35(55.6%) had benign histology. Sensitivity, specificity, positive predictive values and negative predictive values for FNAC and ultrasound were calculated. Out of 34 patients who underwent diagnostic hemi-thyroidectomy, 12(35%) had to undergo completion surgery due to malignant histology. 58% who underwent completion surgery had suspicious features of malignancy in their pre-op US. Conclusion Both ultrasonography and FNAC are cost-effective, minimally invasive investigations in the diagnosis of malignancy in patients with solitary thyroid nodules. However, there is a notable false negative rate in FNAC; hence it is best to incorporate US findings with FNAC in the decision making process in management of solitary thyroid nodules.