Primary Thyroid Tuberculosis Masquerading as a Follicular Neoplasm With Tracheal Compression: A Case Report.

Thyroid tuberculosis (TB) is a rare form of extrapulmonary infection that can mimic thyroid neoplasms. Diagnosis is challenging due to nonspecific imaging and cytology. We report a case of a 77-year-old female with a history of subtotal gastrectomy for gastric adenocarcinoma. Surveillance CT revealed right-lobe-predominant thyroid enlargement causing tracheal compression. Ultrasound showed a multinodular goitre with a 4.1-cm solid nodule (Thyroid Imaging Reporting and Data System (TI-RADS) 3) and a 1.7-cm hypoechoic nodule (TI-RADS 4). Fine-needle aspiration cytology (FNAC) of the smaller nodule suggested a follicular neoplasm. The right thyroid lobectomy was performed. Histology revealed a follicular adenoma with epithelioid granulomas, and polymerase chain reaction (PCR) confirmed Mycobacterium tuberculosis (M. tuberculosis) complex DNA. The patient completed standard anti-tuberculosis therapy and remained asymptomatic at eight months of follow-up. TB should be considered in patients with nodular thyroid disease, particularly when granulomatous inflammation or compressive symptoms are present. Molecular testing facilitates accurate diagnosis, guides therapy, and helps avoid unnecessary surgery.