Complex inferior vena cava malformation initially manifesting as a pulmonary space-occupying lesion: A case report.

The inferior vena cava, the principal retroperitoneal venous trunk, carries deoxygenated blood from the lower extremities, pelvis, and abdominal viscera to the right atrium. Complex inferior vena cava malformations can radiologically mimic pulmonary space-occupying lesions, substantially complicating clinical diagnosis and therapeutic planning. We present the case of a patient in whom contrast-enhanced chest computed tomography incidentally revealed a right-sided intrathoracic mass, initially suspected to be a primary or metastatic pulmonary malignancy. Subsequent dynamic contrast-enhanced computed tomography demonstrated heterogeneous, avid enhancement during the venous phase, raising the possibility of a vascular anomaly. Dedicated magnetic resonance imaging ultimately delineated the mass as a congenital inferior vena cava malformation. This case underscores that intricate inferior vena cava anomalies may masquerade as intrapulmonary masses; misguided surgical intervention could precipitate severe hemorrhagic or thromboembolic sequelae. Multimodality imaging-integrating high-resolution computed tomography and magnetic resonance imaging-is therefore indispensable for accurate differential diagnosis.