Primary Tuberculosis of Thyroid Gland Presenting as a Cold Nodule in a Child: A Case Report

Background: The thyroid gland has traditionally been considered resistant to tuberculosis. However, we report a rare case of extrapulmonary primary tuberculosis in the thyroid gland in a child. Clinical Description: An 8-year-old boy presented with fever for 4 months along with a swelling in the neck for the last 1 month. On examination, the thyroid was enlarged with the right lobe being more enlarged than the left, firm, and mildly tender. Other systemic examination was normal. His mother was treated for tuberculosis 2 years ago. Management and Outcome: Tuberculin test was strongly positive, and the erythrocyte sedimentation rate was raised. Ultrasound thyroid demonstrated a heterogeneously hypoechoic gland, and a technetium scan showed heterogeneous tracer uptake with relative photopenia in the lower poles of the lobes. A granulomatous lesion was demonstrated on fine needle aspiration cytology with CBNAAT detecting the presence of Mycobacterium tuberculosis sensitive to rifampicin. The child was started on antitubercular therapy and responded well. Conclusion: Tubercular involvement of the thyroid, though rare, is possible and may present as a cold nodule. A high index of suspicion, workup, and timely initiation of treatment with antitubercular drugs results in a favorable outcome.