Primary Tuberculosis of the Thyroid Gland Presenting as a Cystic Lesion: Report Two Cases

Abstract

Tuberculosis of thyroid gland (TTB) is extremely uncommon. The incidence is low even in countries where the prevalence of tuberculosis (TB) is endemic and high. The diagnosis is often difficult as the clinical presentation has no distinct characteristics. We report two case of Primary Tuberculosis of the thyroid gland (PTTB) ,one was A 56-year-old man with a lump on the left side of his lower neck. He noticed the swelling 12 weeks prior to presentation and it had been gradually increasing in size. Another was, a 72-year-old man presented with history of left thyroid lobe swelling for 5-7 month, which was gradually increasing in size Ultrasonography disclosed nodules of the left lobe with cystic change. Thyroid function tests were in the normal range, there were no signs of inflammation. There was no evidence of tuberculosis in any other organ.FNA from left lobe of thyroid was performed which yielded purulent aspirate. Smears examined show degenerated inflammatory cells in a necrotic background No follicular epithelial cells were seen. The patients had surgery in which the left lobe was removed. Microscopic examination of the thyroid parenchyma revealed necrotizing epithelioid granulomas with Langhans giant cells. The diagnosis of thyroid tuberculosis was therefore made. The patients was put on isoniazid, rifampicin, ethambutol and pyrazinamid for 2 months and was subsequently given isoniazid and rifampicin for 4 months with a favourable outcome. Although seldom rare presentation of (TTB) observed, tuberculosis should be kept in mind in the differential diagnosis of nodular or cystic lesions of the thyroid.