A 17-year journey of multisystemic hydatid disease with rare iliac bone and sciatic nerve involvement: a case report

Introduction: Cystic echinococcosis (CE) is an endemic parasitic zoonosis causing significant morbidity in pastoral regions of the Middle East. While hepatic and pulmonary involvement predominate, primary or secondary skeletal involvement is extremely rare (<2%), with iliac bone involvement presenting formidable diagnostic and reconstructive challenges. Case presentation: We report the 17-year clinical course of a 27-year-old male livestock handler presenting with recurrent multisystemic hydatidosis. The clinical journey began at age 10 with bilateral pulmonary hydatidosis, progressed at age 19 to disseminated hepatosplenic and peritoneal disease, and culminated at age 26 with extensive infiltrative osteolysis of the right iliac wing and acetabulum. The osseous invasion induced mechanical entrapment of the common peroneal division of the sciatic nerve, resulting in a functional foot drop (motor strength 1/5). An initial misdiagnosis of a bacterial thigh abscess led to inappropriate superficial drainage. Comprehensive imaging revealed classic multilocular “soap-bubble” osteolysis and “racemose” soft-tissue extension. Initiation of a targeted pre-operative albendazole cycle (400 mg twice daily) yielded remarkable neurological recovery (motor strength 3+/5) by reducing pericystic inflammatory edema. Additionally, familial clustering was documented, with four siblings surgically treated for liver CE. Conclusions: This case highlights the propensity of infiltrative iliac hydatidosis to mimic local soft-tissue abscesses or bone tumors in endemic zones. Early recognition, rigorous radiological evaluation, and prompt antiparasitic therapy are crucial to prevent catastrophic misdiagnosis and alleviate secondary compressive neuropathies prior to definitive orthopedic reconstruction.