A 34-year-old female patient was presented to the general surgery clinic of the hospital complaining of a growing tangible swelling in her neck. In physical examination, the patient had two palpable soft nodules in the left lobe of the thyroid which hadn't invaded the surrounding tissues. The function of thyroid gland was normal and fine needle aspiration (FNA) result reported it benign. The patient went through a left lobectomy and isthmectomy. The histopathology report concluded a nodular hyperplasia and a Hydatid cyst. After surgery, the patient was examined searching for any other organs cyst, but there were no cystic lesion in the cranial, thoracic and abdominal cavities. Accordingly, the case was a primary thyroid hydatid cyst, which is rare, even in endemic regions like Iran.
Keywords: Case report; Histopathology; Hydatid cyst; Isthmectomy; Thyroid gland.