Introduction

Canine pheochromocytomas (PHEO) often infiltrate into the intrahepatic caudal vena cava (CVC) at the time of diagnosis. The purpose of this study was to describe the surgical procedure and outcome of en bloc resection of extensive adrenal PHEO including the CVC in dogs.

Materials and Methods

Four dogs (#1–#4) with adrenal mass preoperatively diagnosed by computed tomography (CT) were included. All cases had an extensive adrenal mass invading into the intrahepatic CVC. In addition, CT revealed multiple collateral formation of venous returns caused by the tumor thrombus. In all cases, en bloc resection of the adrenal mass including the CVC was planned. The medical records of all cases were reviewed.

Results

The adrenal mass was the right side in cases #1, #2 and #3, and the left side in case #4. Intraoperative femoral venous pressure was continuously measured. For the en bloc resection, Pringle maneuver, preadrenal CVC occlusion, and/or intrathoracic CVC occlusion were performed in all cases. In addition, the occlusion of right renal vein was combined in case #4. En bloc resection of adrenal mass including the CVC was achieved in all cases. The operation time was between 135 and 212 minutes. Postoperative prognosis was good in all cases except for case #3 that died of acute renal failure on postoperative 4th day.

Conclusions

The feasibility of en bloc resection of extensive adrenal PHEO including the CVC might be determined based on CT findings of collateral venous return and intraoperative monitoring of femoral venous pressure.