Primary thyroid tuberculosis mimicking papillary carcinoma of thyroid: a rare case report

Primary thyroid tuberculosis is an extremely rare extrapulmonary involvement by the causative agent, Mycobacterium tuberculosis. Its rarity and resemblance to thyroid malignancy led to unnecessary aggressive operative interventions.

A 54-year-old female presented with recent onset dysphagia and foreign body sensation in the throat for 3 months, and anterior neck swelling since last 10 years.

A single nodular firm anterior neck swelling was present which moves with deglutition. Thyroid function test was normal. Ultrasonography thyroid revealed TIRADS-3. Fine-needle aspiration cytology was suggestive of papillary carcinoma of thyroid.

Total thyroidectomy with central compartment neck dissection was performed. Histopathology of the thyroid specimen revealed tubercular thyroiditis. Postoperatively, Mantoux test and interferon gamma radioassay were positive. Antitubercular therapy was given for total of 6 months.

With ultrasonography-guided fine-needle aspiration cytology, preoperative diagnosis of primary thyroid tuberculosis is quite challenging even in tuberculosis endemic countries. So, it should be considered one of the differential diagnoses despite negative relevant history and without clinical cervical lymph nodes involvement with cytology proven suspicious papillary thyroid cancer before proceeding for surgical intervention.