Endocrine Abstracts

Background: Tuberculous (TB) lymphadenitis can mimic cervical node metastasis from papillary thyroid carcinoma (PTC) since the distribution and appearance of affected lymph nodes is similar.

Case: A 50-year-old Filipino presented with a gradually-enlarging anterior neck mass, with a solitary lymph node palpated at the left cervical area. The rest of the history, physical examination and blood workup were unremarkable. A thyroid ultrasound showed a 6.5×5×3 cm solid left thyroid mass plus a single 1.2×1×0.5 cm cervical lymph node. Fine-needle aspiration biopsy (FNAB) of the thyroid mass revealed PTC. The patient underwent total thyroidectomy with node dissection where histopathology confirmed follicular variant (FV)-PTC. Lymph node examination, however, revealed granulomatous inflammation with caseation necrosis and Langhans giant cells consistent with TB. A chest X-ray plus two acid-fast stained sputum samples were negative for concomitant pulmonary TB. The patient underwent standard anti-mycobacterial therapy.

Discussion: Our patient had an enlarging anterior neck mass with an associated lymph node. Due to the documented thyroid malignancy on FNAB plus lymph node proximity, primary consideration for lymphadenopathy was metastasis. However, the distribution and sonographic appearance of lymph nodes is identical in TB adenitis and cervical node metastasis. Since current guidelines do not recommend routine preoperative FNAB of lymph nodes in PTC (which is staged clinically and radiologically), the diagnosis of TB lymphadenitis can be easily missed. In retrospect, it could have identified TB preoperatively, leading to earlier anti-mycobacterial therapy and avoiding neck dissection. This is the first documented case in Southeast Asia, a high TB burden region. This is also the first report involving FV-PTC, which has features between those of conventional PTC and follicular thyroid carcinoma.

Conclusion: In endemic areas, TB should be a differential in the etiology of cervical lymphadenopathy in PTC patients. Proper preoperative evaluation is important, and guidelines may need to be revised.