Massive Inferior Vena Cava Thrombosis and Pulmonary Embolism Secondary to Hepatic Hydatid Cyst: A Fatal Case.

BACKGROUND Hydatid disease, caused by Echinococcus granulosus, is an endemic parasitic infection that predominantly affects the liver. Although slow-growing and asymptomatic, large hepatic cysts lead to catastrophic vascular complications, including inferior vena cava (IVC) thrombosis and pulmonary embolism (PE). Although rare, life-threatening events require prompt recognition and multidisciplinary management to optimize outcomes. CASE REPORT A 68-year-old woman with paroxysmal atrial fibrillation presented with right upper-quadrant pain, fever, and poor oral intake for several weeks. Examination revealed abdominal distension, hepatomegaly, and mottled, cold lower limbs. Laboratory findings showed severe metabolic acidosis and leukocytosis, indicating significant systemic involvement and possible sepsis. Computed tomography (CT) angiography demonstrated a pulmonary embolism, a giant (29×18 cm) right hepatic cyst exerting a mass effect, and extensive thrombosis extending from the infrarenal IVC to both external iliac veins. Echocardiography showed extrinsic cardiac compression without signs of tamponade but with functional compromise related to mass effect. Management included anticoagulation, albendazole, broad-spectrum antibiotics, vasopressors, and continuous renal replacement therapy. Ultrasound-guided percutaneous drainage of the cyst yielded 4 L of purulent fluid, with transient improvement in limb perfusion suggesting partial decompression of venous outflow obstruction. An IVC filter was inserted, but despite intensive therapy, the patient developed refractory shock and died due to progressive hemodynamic collapse and multiorgan failure. CONCLUSIONS Massive hepatic hydatid cysts can precipitate IVC thrombosis and PE through mechanical compression or infection-related inflammation. Early diagnosis, multidisciplinary coordination, and timely surgical or percutaneous decompression are vital to prevent death.