Surgery and toceranib for renal cell carcinoma with caval thrombus in a dog.

A 14-year-old spayed female papillon dog was presented with hematuria and a right renal mass. Contrast-enhanced computed tomography revealed a tumor thrombus extending about 1.5 cm cranially from the right renal vein into the caudal vena cava (CVC), consistent with renal cell carcinoma and caval thrombus, with no signs of distant metastasis. The dog underwent open right-sided nephrectomy and CVC thrombectomy, using 2 tourniquets, with a total occlusion time of 12 min 13 s. Transient hypotension during surgery was successfully managed, and there were no major intra- or postoperative complications. Histopathology confirmed a highly malignant renal cell carcinoma with vascular invasion. Adjuvant toceranib therapy was initiated to address potential microscopic residual disease. Pulmonary metastasis was detected on Day 553 after surgery, and the dog remained alive on Day 722. This case demonstrates that renal cell carcinoma with caval thrombus in dogs can be surgically managed without severe complications. Moreover, adjuvant toceranib therapy can be used safely. Together, these findings offer valuable insights into the feasibility and safety of surgical strategies for CVC-invasive renal tumors in dogs. Key clinical message: Renal cell carcinoma with caval thrombus in dogs can be safely managed with surgery, highlighting the feasibility of aggressive surgical intervention for this rare condition.