Tuberculous thyroiditis is a very rare disease. Its clinical features are non-specific in most of the cases, mimicking other thyroid diseases. Confusions most frequently made are those with thyroid cancer and toxic nodular goiter. Therefore, diagnosis often comes as a histopathological surprise, after thyroid ablation for other reasons.
Thyroid tuberculosis was diagnosed histopathologically in six out of 1232 cases of thyroid surgery. Preoperatory diagnosis was of toxic nodular goiter in two cases, and of thyroid carcinoma in the other four. We diagnosed other two cases of thyroid tuberculosis out of 2291 nodular goiters investigated by FNAB. The two patients were initially suspected of thyroid carcinoma and acute bacterial thyroiditis, respectively. Axillary lymph node biopsy in the first case showed the presence of giant epithelioid cell granulomas, with evolution toward caseous necrosis. Signs of inflammation accompanied by caseation were found in thyroid aspirates in both subjects. Löwenstein culture allowed the isolation of mycobacterium tuberculosis.
Fine needle aspiration biopsy allows establishing the diagnosis before surgical intervention. Presence of epithelioid granulomas with necrosis and of acid-fast bacilli in the aspirate is very specific. When central caseous necrosis is present, the thyroid lesion is highly suspectable of being tuberculous even in the absence of cellularity. Further culture of the biopsy product on special media is then mandatory. Preoperatory diagnosis of thyroid tuberculosis may modify the therapeutic attitude.
03 - 07 May 2008
European Society of Endocrinology