Iatrogenic tumor seeding after ureteral stenting in a dog with urothelial carcinoma.

A 5 yr old castrated male miniature dachshund presented with clinical signs attributable to carcinoma involving the bladder neck and prostate. On day 84 following diagnosis, the dog developed bilateral ureteral obstruction and ureteral stenting was attempted. The stents were inserted in a normograde fashion via percutaneous puncture of the dilated renal pelvises. Two wk later, the dog developed nodules at both sites of renocentesis. En block resection of the masses was performed, and histologic examination confirmed that the masses were urothelial carcinoma, likely caused by iatrogenic tumor seeding. Ureteral stenting is a useful technique to relieve malignant ureteral obstruction; however, risk of iatrogenic tumor seeding must be considered.