Primary Renal Neoplasia of Dogs

Background:Primary renal tumors are diagnosed uncommonly in dogs. Hypothesis:Signs and survival will differ among different categories of primary renal tumors. Animals:Data were collected from the medical records of 82 dogs with primary renal tumors diagnosed by examination of tissue obtained by ultrasound‐guided biopsy, needle aspiration, surgery, or at postmortem examination. Methods:This was a multi‐institutional, retrospective study. Results:Forty‐nine dogs had carcinomas, 28 had sarcomas, and 5 had nephroblastomas. The dogs were geriatric (mean 8.1 years; range: 1–17) with a weight of 24.9 kg (range: 4.5–80). Tumors occurred with equal frequency in each kidney with 4% occurring bilaterally. Initial signs included one or more of hematuria, inappetance, lethargy, weight loss, or a palpable abdominal mass. Pain was reported more frequently in dogs with sarcomas (5/28). The most common hematologic abnormalities were neutrophilia (22/63), anemia (21/64), and thrombocytopenia (6/68). Polycythemia was present in 3 dogs and resolved with treatment. Hematuria (28/49), pyuria (26/49), proteinuria (24/50), and isosthenuria (20/56) were the most frequently observed abnormalities on urinalysis. Pulmonary metastases were noted on thoracic radiographs in 16% of dogs at diagnosis. Seventy‐seven percent of dogs had metastatic disease at the time of death. Median survival for dogs with carcinomas was 16 months (range 0–59 months), for dogs with sarcomas 9 months (range 0–70 months), and for dogs with nephroblastomas 6 months (range 0–6 months). Conclusions and Clinical Importance: Primary renal tumors in dogs are generally highly malignant with surgery being the only treatment that improves survival.