Planned en bloc resection using veno-venous bypass for an extensive retroperitoneal sarcoma with a caval thrombus in a dog.

Objective: To report the successful complete resection of an extensive retroperitoneal sarcoma (RPS) with a caval thrombus using veno-venous bypass (VVB) to facilitate temporary caudal vena cava (CVC) occlusion.

Study design: Case report.

Animal: A 12-year-old neutered male Standard Poodle.

Methods: Computed tomography (CT) revealed an extensive mass originating from the right adrenal gland region with an associated caval thrombus extending into the thoracic CVC. A preemptively planned en bloc resection, including the right kidney and caval thrombus, was performed. VVB and a Pringle maneuver were used to minimize hemorrhage and maintain hemodynamic stability.

Results: Surgery was successfully completed without major complications. The operative time was 161 min, with Pringle maneuver duration of 4 min 8 s and a caval occlusion time of 44 min 43 s. The dog's general condition stabilized the following day with no decline in renal function. The histopathologic examination confirmed the diagnosis of RPS. The dog remained in good health with no recurrence or metastasis at the 1-year follow-up.

Conclusion: This is the first report of a clinical application of VVB during temporary caval occlusion to achieve complete en bloc resection of an extensive adrenal RPS with ipsilateral kidney and caval thrombus, followed by repair of a CVC incision. VVB may be a valuable technique for maintaining hemodynamic stability and reducing hemorrhage during complex oncological surgeries requiring temporary caval occlusion.