Polycythemia associated with renal fibrosarcoma in a dog.

A 10-year-old Beagle-type dog with intermittent vomiting and anorexia had an absolute polycythemic condition. A renal mass was detected and removed by total nephrectomy. After surgery, the hematologic values returned to normal, suggesting that the tumor was the cause of the polycythemia. The histologic diagnosis was fibrosarcoma. In dogs, secondary polycythemia has otherwise been reported with renal carcinoma and lymphosarcoma.