INTRODUCTION The thyroid gland is a very rare focus of tuberculosis. The reported prevalence varies from 0.1 to 0.6% in histo- logically diagnosed specimens to 0.6 to 1.15% in patients undergoing fine-needle aspiration (FNA) cytology (1,2). Fewer than 50 cases of tuberculous thyroiditis have been reported from India, where the prevalence of tuberculosis is high (3). The exact reason for the rarity of involvement of this site is unclear. Potential factors include the extremely high blood flow and the high iodine content of the colloid, which possibly has a bactericidal action (4). The increased phagocytic activity of the intrathyroidal lymphocytes may also limit infection in patients with associated hyperthyroidism. We report two cases of thyroid tuberculosis with varied initial clinical manifesta- tions. REPORT OF CASES Case 1 A 46-year-old woman presented with midline neck swelling that had gradually increased for 2 months. She had no symptoms suggestive of hypothyroidism or hyper- thyroidism nor of tracheal or esophageal compression. In addition, she denied having any history of neck pain, fever, or weight loss. On physical examination, the patient had a nontender, diffuse, firm, grade III goiter and no cervical lymph node enlargement. Results of laboratory investigations were as follows: hemoglobin 11.2 g/dL, total leukocyte count 8.6 × 10 3 /µL (normal, 4.0 to 11.0), erythrocyte sedimentation rate 60 mm in 1 hour (normal, 0 to 20), serum triiodothy- ronine 29 ng/dL (normal, 60 to 120), thyroxine 2.9 µg/dL (normal, 4 to 12), and thyroid-stimulating hormone (thy- rotropin) 29 µIU/mL (normal, 0.5 to 5.2). FNA cytology of the thyroid gland showed epithelioid granulomas with Langhans’ giant cells (Fig. 1), and stain for acid-fast bacil- li (AFB) was positive. Culture for Mycobacterium was sterile. Findings on chest radiography were normal, and a tuberculin test was strongly positive (skin reaction, 23 by 22 mm). Thyroid microsomal antibody titers were insignificant. The patient was treated with levothyroxine in increas- ing doses up to 150 µg/day and antituberculous drugs consisting of isoniazid, rifampicin, ethambutol, and pyraz- inamide. All four antituberculous agents were given for the initial 8 weeks, and then isoniazid and rifampin were continued for the next 16 weeks. After completion of 6 months of antituberculous therapy, the patient was asymp- tomatic, and levothyroxine therapy had yielded remark- able reduction in goiter size. Case 2 A 44-year-old man presented with a painless, gradu- ally increasing midline neck swelling of 1-month duration. He had a history of fever, anorexia, weight loss, and right cervical node enlargement 9 months before the current presentation. Findings on FNA from the cervical lymph node were suggestive of tuberculosis, and stain for AFB was positive. He was given antituberculous therapy, which he received for 8 months (isoniazid, rifampicin, ethambutol, and pyrazinamide for 2 months, followed by isoniazid and rifampicin for the next 6 months), before the current consultation because of the neck swelling. He had no history of fever, weight loss, or compressive symptoms associated with the neck swelling. On physical examination, the patient had a nontender enlargement of the left lobe of the thyroid gland but no cervical lymph node enlargement. Laboratory studies revealed the following: hemoglobin 12.0 g/dL, total TUBERCULOSIS OF THE THYROID GLAND: REPORT OF TWO CASES Pavanasam Velayutham, MD,* 1 Anil Bhansali, DM, 1 Mahadevan Shriraam, MD,* 1 Manikkapurath Hemachandran, MD, 2 and Niranjan Khandelwal, MD 3 Submitted for publication April 16, 2003 Accepted for publication October 22, 2003 *Endocrinology fellow-in-training. From the Departments of 1 Endocrinology, 2 Pathology, and 3 Radiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Address correspondence and reprint requests to Dr. Anil Bhansali, Department of Endocrinology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 160012. © 2004 AACE. 284 ENDOCRINE PRACTICE Vol 10 No. 3 May/June 2004 Endocrine Fellows Case Conference Abbreviations: AFB = acid-fast bacilli; FNA = fine-needle aspiration; TB-PCR = polymerase chain reaction for Mycobacterium tuberculosis