Thyroid Tuberculosis: Misdiagnosed as Papillary Thyroid Carcinoma - A Rare Case Report.

Background: Thyroid tuberculosis (TTB), either in its primary or secondary form, is a rare occurrence, even in recent years, with a high incidence of tuberculosis in China. Nowadays, with the increasing morbidity of thyroid nodules, it is apt to be misdiagnosed with malignant tumors. In this case, a suspicious malignant lesion was found on thyroid ultrasound (US), but the result after the surgery showed TTB. Case Presentation: This article reported a 67-year-old woman who was found left thyroid nodules during a physical examination three month ago. Thyroid US showed two suspicious hypoechoic lesions in the left thyroid gland and diagnosed as Chinese Thyroid Imaging Reporting and Data System. (C-TI-RADS) 4A category. The patient underwent US-guided fine needle aspiration of the two lesions, the results of which showed that suspected malignant tumors were not excluded. The patient underwent a left thyroidectomy and central group lymph node dissection. Postoperative pathological examination showed granulomatous inflammation with caseous necrosis in the thyroid gland, and diagnosed as tuberculosis. The patient had nonspecific clinical symptoms, no history of exposition, and no pulmonary involvement. Subsequently, the patient visited the tuberculosis specialist outpatient clinic for treatment. Conclusion: This case report aims to enhance clinicians' awareness of TTB. With the increasing detection rate of thyroid nodules in US, it is crucial to distinguish between benign and malignant ones. TTB is often overlooked. Considering the existence of tuberculosis, unnecessary surgical treatment can be avoided.