[A thyroid pathology: The great simulator].

INTRODUCTION: Tuberculosis remains a major public health problem in developing countries. Thyroid localization is very rare, and often the cause of misdiagnosis. Pathological anatomy plays an important role in the diagnosis of certainty. The authors report a case of primary thyroid tuberculosis in a 22-year-old patient. We highlight the epidemiological particularities of this case, and discuss diagnostic methods and the contribution of pathological anatomy.

OBSERVATION: A 22 year-old male patient, with no reported pathological history, was seen in the clinic for the management of an isolated anterior cervical swelling that had been evolving for two months. Clinical examination revealed only a small thyroid nodule, with no inflammatory or vascular features. Biological tests were unremarkable. Ultrasound revealed a 2.4cm hypoechoic, homogeneous, poorly vascularized tissue mass in the left lobe, classified as EU-TIRADS 3. Fine needle aspiration with cytopathological study revealed a necrotizing granulomatous lesion suggestive of tuberculosis. A lobo-isthmectomy was performed, and histopathology revealed thyroid parenchyma destroyed by tubercular granulomas. The postoperative course was straightforward, with an exeat on postoperative day 6. Anti-tuberculosis treatment was instituted for 6 months. Three- and six-month follow-up examinations were unremarkable. The evolution was favorable, with recovery after treatment.

CONCLUSION: Primary thyroid tuberculosis is rare. Cytology is important for orientation, and often helps to avoid misdiagnosis. The diagnosis should be considered in the presence of any thyroid mass in a patient from a tuberculosis-endemic region.