Abstract
INTRODUCTION: Hydatid cysts caused by Echinococcus granulosus are zoonotic infections endemic to pastoral regions. While hepatic (50 - 70%) and pulmonary (20 - 30%) involvement dominate, primary thyroid hydatidosis is exceptionally rare (< 1% of cases), posing diagnostic and therapeutic challenges. This case underscores the importance of considering parasitic etiologies in thyroid nodules, particularly in endemic zones. CASE PRESENTATION: A 26-year-old female patient presented with complaints of pain and swelling in the anteroposterior region of the neck, predominantly on the right side. Fine needle aspiration (FNA) from the nodule seen on ultrasound (US) of the thyroid gland was reported to be suspicious for papillary thyroid carcinoma (PTC), and the patient underwent bilateral total thyroidectomy. In the postoperative histopathological examination, a hydatid cyst was confirmed in the thyroid gland. CONCLUSIONS: Thyroid hydatid cysts, though rare, require high clinical suspicion in endemic regions. Imaging (US/MRI) and serology are pivotal for preoperative diagnosis, while FNA is contraindicated. Complete surgical excision with adjuvant albendazole ensures optimal outcomes. Public health measures, including dog deworming and community education, are critical to disrupting the parasite's lifecycle.