Posterior nutcracker syndrome with acute left renal vein thrombosis and floating thrombus in inferior vena cava with acute renal infarction: A rare case report

Background: Nutcracker syndrome (NCS) is a rare vascular compression disorder caused by the entrapment of the left renal vein (LRV), leading to renal venous hypertension. Posterior nutcracker syndrome (PNCS), where the LRV is compressed between the aorta and the vertebral column, is even rarer and presents a diagnostic challenge due to its variable clinical manifestations. Case Presentation: We report a rare case of PNCS complicated by LRV thrombosis and renal infarction, successfully managed with conservative treatment and invasive procedures. The patient presented with hematuria and left flank pain. Imaging studies confirmed PNCS with LRV floating thrombus extending into the inferior vena cava (IVC). While PNCS-associated renal vein thrombosis has been reported, the coexistence of multiple thrombophilic abnormalities further complicated the clinical course in this case. Medical therapy with anticoagulation successfully preserved renal function and a retrievable IVC filter was placed to prevent pulmonary embolism (PE) from floating caval component of the thrombus. Discussion: Conservative treatment with anticoagulation should be the primary approach in managing LRV thrombosis, even when associated with NCS. Endovascular interventions, such as prophylactic IVC filter placement, should be considered. Given the occurrence of PE in the presence of a free-floating caval thrombus, IVC filter placement may be required to prevent further embolic events. Conclusion: This case highlights the importance of early recognition and individualized management strategies in PNCS with LRV thrombosis. Conservative therapy with anticoagulation remains first-line approach, with endovascular procedures reserved for select patients. Further studies are needed to guide optimal management in such rare presentations.