Extensive caudal vena cava thrombosis secondary to unilateral renal tubular cell carcinoma in a dog

A nine-year-old German shorthaired pointer cross was admitted because of partial anorexia, exercise intolerance and haematuria. On clinical examination, subcutaneous oedema, purpura and ascites were detected along with a palpable mass in the right craniodorsal abdomen. Laboratory findings included regenerative anaemia, leucocytosis, thrombocytopenia, azotaemia, increased blood serum alkaline phosphatase and proteinuria. Radiographic and ultrasonographic examinations revealed a large neoplasm involving the right kidney. Computed tomography further showed that the neoplastic tissue had spread into the lymph nodes, the wall of the caudal vena cava, the liver and lungs. The right renal vein, caudal vena cava and iliac veins appeared enlarged and secondarily thrombosed. A diagnosis was made of renal tubular cell carcinoma with secondary venous thrombosis. Gross postmortem examination confirmed the imaging findings, while light and electron microscopic examination revealed that the neoplasm was a solid carcinoma originating from the proximal convoluted renal tubules.