Concurrent renal adenocarcinoma and polycythemia in a dog.

Concurrent renal adenocarcinoma and polycythemia were diagnosed in a 19-month-old, female Rhodesian ridgeback. An unusually early presentation for this neoplasm, it is the second reported case of renal adenocarcinoma in a dog less than two years of age. Concurrent renal adenocarcinoma and polycythemia have been reported previously in four older dogs. In the dog of this report, clinical signs included brick-red mucous membranes, lethargy, a periodic systolic heart murmur, and engorged retinal vessels. A large retroperitoneal mass and pulmonary metastatic nodules were present at the time of diagnosis. Red blood cell count, packed cell volume, and hemoglobin concentration were greatly increased (12,940,000 red blood cells/microliter; 73.2%; and 26.6 g/dl, respectively). Histopathological diagnosis was renal adenocarcinoma. Polycythemia was the result of excessive erythropoietin production by the neoplasm.