Primary tuberculosis of the thyroid gland.

Thyroid tuberculosis is a rare disease even in countries in which tuberculosis (TB) constitutes an endemic disorder. The diagnosis is often difficult as the clinical presentation has no distinct characteristics. We report a 47-year-old woman who presented with a painful nodular swelling of the neck, confirmed by physical examination and sweating. Ultrasonography disclosed nodules of the pyramidal lobe with cystic change, and bilateral multiple hypoechogenic lymph nodes along the jugular and carotid chains. Thyroid function tests were in the normal range, there were no signs of inflammation and the tuberculin test was negative. There was no evidence of tuberculosis in any other organ. The patient had surgery in which the pyramidal lobe was removed. Microscopic examination of the thyroid parenchyma and the excised lymph node revealed necrotizing epithelioid granulomas with Langhans' giant cells. The diagnosis of thyroid tuberculosis was therefore made. The patient was put on isoniazid, rifampicin, ethambutol and pyrazinamid for the subsequent 2 months and was subsequently given isoniazid and rifampicin for the subsequent 6 months with a favourable outcome. Although seldom observed, tuberculosis should be kept in mind in the differential diagnosis of nodular lesions of the thyroid.