Maxillary Osteosarcoma in a Prairie Dog (Cynomys Ludovicianus)

Abstract

Abstract. To date, few tumors have been identified in prairie dogs, with odontoma being the most common. Osteosarcoma has been documented in a wide range of species, including a number of rodents. In this case, a locally invasive maxillary osteosarcoma was diagnosed in a prairie dog. Gross examination revealed a pale, tan, lobulated, sessile maxillary mass extending ventrally into the oral cavity from the hard palate and the gingiva surrounding the upper right cheek teeth. The mass invaded the right nasal cavity and retrobulbar space causing exophthalmia. Microscopically, the mass consisted of densely packed spindleshaped cells with occasional multinucleated giant cells. Brightly eosinophilic osteoid was multifocally scattered in the tumor mass. To the authors' knowledge, this is the first documented report of maxillary osteosarcoma in a prairie dog.

A Retrospective Study of Tumours in Black-Tailed Prairie Dogs (Cynomys ludovicianus) Submitted to a Zoological Pathology Service

“…Maxillary osteosarcoma, previously demonstrated by Mouser et al (2006), and epiglottal fibrosarcoma previously demonstrated by Suedmeyer and Pace (1994), were not noted in any prairie dog in this study. In one study a gastric adenocarcinoma with hepatic metastasis, a renal adenocarcinoma and an oral squamous cell carcinoma with renal metastasis were found in three captive male prairie dogs (Grinner, 1983).…”

“…Garner 1999;Phalen et al, 2000;Wagner and Johnson, 2001;Boy and Steenkamp, 2006). Repeated trauma and fractures to the incisors caused by chewing on cage bars, falling from a height or dental trimming with subsequent trauma of the bone surrounding the incisors, resulting in bony changes that impede the tooth growth, have been proposed as possible causes of elodontomas in prairie dogs (Wagner, 1999;Phalen et al, 2000;Capello, 2002Capello, , 2005Capello, , 2008Boy and Steenkamp, 2006). Another suggested cause is chronic intermittent vitamin A deficiency, which experimentally reproduces apical dysplasia and formation of elodontomas of the upper incisors in rats (McDowell et al, 1987;Crossley, 2004).…”

“…The most common clinical sign of elodontoma is dyspnoea due to obstructive respiratory disease (Wagner, 374 I. Thas and M.M. Garner 1999;Phalen et al, 2000;Wagner and Johnson, 2001;Boy and Steenkamp, 2006). Repeated trauma and fractures to the incisors caused by chewing on cage bars, falling from a height or dental trimming with subsequent trauma of the bone surrounding the incisors, resulting in bony changes that impede the tooth growth, have been proposed as possible causes of elodontomas in prairie dogs (Wagner, 1999;Phalen et al, 2000;Capello, 2002Capello, , 2005Capello, , 2008Boy and Steenkamp, 2006).…”

“…There is limited information on diseases in prairie dogs with the most common diagnoses being elodontoma (Wagner, 1999;Phalen et al, 2000;Wagner and Johnson, 2001;Capello, 2002Capello, , 2005Boy and Steenkamp, 2006) and hepatocellular adenocarcinoma (Woolf et al, 1982;Une et al, 1996;Garner et al, 2004). This report summarizes the spectrum of neoplastic diseases in this species diagnosed in a private zoological pathology service.…”

Anatomy and Disorders of the Oral Cavity of Rat-like and Squirrel-like Rodents

“…They tend to be highly invasive in mice, leading to infiltration of bone and other structures of the head and should therefore be taken into consideration in the list of differentials. A maxillary osteosarcoma has been reported in a prairie dog 56 and an adenocarcinoma of the buccal salivary gland has been described in a Richardson ground squirrel. 57 Electrical injuries are not uncommonly seen in domestic rodents, as a result of chewing on power cables and subsequent direct body contact with an electrical source.…”