Research Update: Clinicopathologic features of retroperitoneal sarcomas in dogs

In this retrospective study from a veterinary teaching hospital, the medical records of 14 dogs with tumors of the retroperitoneal space (excluding those arising from the kidneys, adrenal glands, or ureters) were reviewed. The tumors were diagnosed at necropsy in two of the dogs and during exploratory surgery in 12 of the dogs. The median age of the dogs was 9 years, and most of the dogs were large-breed (median weight = 60.9 lb [27.7 kg]).

Most clinical signs were nonspecific (lethargy or collapse) or neurologic (lower motor neuron lameness). The physical examinations most frequently revealed an abdominal mass (six dogs) or abdominal or retroperitoneal pain (five dogs). Hematologic abnormalities included anemia (10 dogs), lymphopenia (eight dogs), red blood cell morphologic changes (seven dogs), and elevated aspartate aminotransferase (nine dogs) and creatine kinase (seven dogs) activities. Abdominal imaging revealed a mass in all the dogs regardless of the modality used.

Surgery revealed a mass originating from the epaxial muscles (nine dogs) or retroperitoneal space (five dogs). Treatments involved complete resection, cytoreductive surgery and intraoperative radiation, incisional biopsy only, and adjuvant chemotherapy. Hemangiosarcoma was the most commonly identified tumor (nine dogs). The median survival time for all dogs was 37.5 days.

Liptak JM, Dernell WS, Ehrhart EJ, et al. Retroperitoneal sarcomas in dogs: 14 cases (1992-2002). J Am Vet Med Assoc 2004;224:1471-1477.

COMMENTARY

Tumors of the retroperitoneal space have been infrequently described in the veterinary literature. The results of this report should alert practitioners to the possibility of a serious lesion in dogs with vague blood dyscrasias and signs referable to the dorsal abdominal or spinal region. Imaging with radiography, ultrasonography, or computed tomography, as used in this study, is critical in confirming a mass. Early diagnosis of a small tumor may enhance the efficacy of surgical resection and adjuvant therapies in reducing metastases and recurrence. The prognoses in these patients in this report were, unfortunately, poor.

The information in "Research Updates" was provided by Veterinary Medicine Editorial Advisory Board member Joseph Harari, MS, DVM, DACVS, Veterinary Surgical Specalists, 21 E. Mission Ave., Spokane, WA 99202.

Joseph Harari, MS, DVM, DACVS