Dr Muhammad Farooq Tahir, Dr Mughira Tahir Ch, Dr Maryam Tanveer
Purpose: Ultrasound Guided Fine Needle Aspiration (US-FNAB) is a safe and effective method of screening for malignant thyroid nodules such as papillary thyroid cancer. However, there is little data on the diagnostic efficacy of US-FNAB in papillary thyroid microcarcinoma (≤10 mm in diameter). We aim to compare the diagnostic efficacy of USFNAB on thyroid nodules between two groups divided by a diameter of 10 mm by correlating the cytological results of US-FNAB with the histopathologic diagnoses in selected patients. Place and Duration: In the Surgical Unit-II of Services Hospital Lahore for one-year duration from May 2019 to May 2020. Patients and Methods: Eight hundred and twenty-two thyroid nodules (group A: diameter ≤10 mm, n = 620; group B: diameter> 10 mm, n = 202) from 797 patients treated between March 2014 and June 2017 were evaluated retrospectively. Only nodules with categories 4-6 Thyroid Imaging Reporting and Data System (TIRADS) were qualified and collected by the US-FNAB, and then surgically resected. Results: According to the diagnostic categories,94 thyroid nodules were classified as I, III, and IV and were excluded from the analysis. 728 thyroid nodules from 721 patients were analyzed. The malignancy rates in the US-FNAB were 88.2% and 84.6% (p = 0.202) in groups A and B, respectively, and the malignancy rates were 89.5% and 86.9% (p = 0.330), respectively in histopathology. There was a high agreement between the cytological and histopathological diagnoses (kappa value = 0.797) and no statistical difference in the accuracy of US-FNAB was found between the two groups (p = 0.533). Conclusion: In the case of thyroid nodules of the category 4-6 TIRADS, the diagnostic efficacy of US-FNAB is similar in the case of thyroid nodules smaller or larger than 10 mm in diameter. Key words: ultrasound guided fine needle aspiration biopsy, thyroid nodules, microcarcinoma, histopathology, cytopathology.