Thyroid tuberculosis diagnosed as papillary thyroid carcinoma with fever of unknown origin.

Thyroid tuberculosis is a rare disease, very few cases have been reported. It is difficult to diagnose because of no typical characteristics. We report on a patient who underwent surgery for suspected thyroid carcinoma, but who was then diagnosed with thyroid tuberculosis. The patient was a woman in her 70s. She had been diagnosed with chronic renal failure and had been on peritoneal dialysis. She complained of fever and a painful left anterior neck swelling. Computed tomography showed thyroid tumor with cervical lymph node swelling, ultrasound-guided fine needle aspiration cytology was suspected for papillary thyroid carcinoma. We performed surgery to confirm the diagnosis and determine treatment. Procedures for thyroid carcinoma were followed, including left lobectomy of the thyroid gland, central lymph node dissection and right cervical lymph node resection. Pathological examination found no malignant findings in the thyroid tissue but did find a granulation layer even in the right cervical lymph node. Tuberculosis-specific IFN-γ assay was positive, we diagnosed thyroid and cervical lymph node tuberculosis. Postoperatively, the neck pain and fever improved, she was treated as an outpatient with antituberculosis drugs therapy. Thyroid tuberculosis must be considered in patients with immunocompromised, such as this patient, who was on peritoneal dialysis.