Hydatid Cyst in the Thigh: An Uncommon Presentation of Cystic Echinococcosis

Abstract Introduction: Hydatid cyst, a parasitic infection is primarily caused by cystic echinococcosis primarily infecting liver most commonly followed by lungs. However, it can also occur at some extra hepatic and extra pulmonary location such as thigh with a very low incidence rate. This case report aims to underscore the importance of considering hydatid cysts as a differential diagnosis for swelling in the thigh. Case Presentation: A 19 year old male presented with a palpable mass in the medial aspect of his right thigh, accompanied by intermittent pain and swelling from last 1 year. The patient had no recent travel history to endemic regions but had a history of contact with livestock. Imaging studies, including ultrasound and MRI, revealed a large, well-defined cystic mass with characteristic features suggestive of a hydatid cyst. Serological tests confirmed the diagnosis of hydatid disease. Discussion: Patients with hydatid cysts of thigh often present with localized swelling, pain, and reduced range of motion. Diagnostic imaging, including ultrasound (USG), computed tomography (CT), and magnetic resonance imaging (MRI), is essential to identify the cyst's location, its size, and potential complications. Serological tests, such as (ELISA) enzyme-linked immunosorbent assays, also support the diagnosis. Treatment involves surgical removal of the cyst with complete excision to prevent recurrence and postoperative treatment typically involves anti-parasitic medication to eradicate any residual infection. Conclusion: Hydatid cysts of thigh, while rare, should be considered in the differential diagnosis of soft tissue masses. Early recognition and appropriate surgical management are key to successful treatment and prevention of recurrence. Further research is needed to optimize diagnostic protocols and postoperative care for this unusual presentation of Echinococcosis.