Primary tuberculosis of the thyroid gland: a case report.

Tuberculosis of the thyroid gland is an uncommon disease and primary involvement of thyroid is even more rare. It is a rare disease even in countries in which tuberculosis is endemic. The diagnosis is often difficult as the clinical presentation has no distinct characteristics. Clinical course of the disease may resemble toxic goiter or acute thyroiditis or may follow a subacute or chronic growth pattern without specific symptomatology. Histologically presence of necrotizing epithelioid cell granulomas along with langhans type giant cells are the hallmark of thyroid tuberculosis. Demonstration of acid fast bacilli by ZN staining confirms the diagnosis, but this stain is frequently negative in tissue sections.