Tuberculosis of the thyroid gland: A rare case report

Abstract

Abstract Tuberculosis (TB) of the thyroid gland is exceedingly rare, even in regions like India, where tuberculosis is prevalent, with an estimated incidence of 0.1–0.4%. While tuberculosis can affect various organs, its involvement in the thyroid, pancreas, striated, and cardiac muscle is uncommon. Diagnosis poses a challenge due to the lack of distinctive clinical features—microscopic examination revealing epithelioid granulomas, sometimes with caseous necrosis and Langhans-type giant cells, aids in diagnosis. Confirmation typically involves detecting acid-fast bacilli through staining techniques like Ziehl Neelsen (ZN), molecular diagnostic methods such as TB Gene Expert or polymerase chain reaction for Mycobacterium tuberculosis (TB PCR), and histopathological examination of excised specimens. Recently, we encountered a case involving a 21-year-old male presenting with a 2-month history of diffuse neck swelling. Clinical examination suggested thyroid swelling, confirmed by ultrasound, showing a cystic lesion with necrotic areas, suggestive of thyroiditis, accompanied by bilateral cervical lymphadenopathy. Fine Needle Aspiration Cytology revealed necrotizing granulomatous thyroiditis, prompting further investigation for tuberculosis. TB Gene Expert and ZN staining performed on fine needle aspiration cytology (FNAC) material confirmed tuberculosis, leading to anti-tuberculous treatment, which resulted in a positive response. In presenting this case, we aim to highlight the rarity of tuberculosis affecting the thyroid gland and emphasize the importance of considering minimally invasive diagnostic methods, such as FNAC and molecular techniques, before resorting to surgical interventions. This case underscores the significance of clinicians’ awareness regarding unusual tuberculosis presentations and the availability of advanced diagnostic tools to ensure timely and appropriate management.