Abstract
A perceived increase in the number of neoplastic cases in a captive population of red kangaroos (Macropus rufus) and paucity of reports of macropod neoplasms in general, prompted a review of all kangaroo deaths from 1992–2002 at the Kansas City Zoo. Twenty-eight kangaroos died during this study period, and all animals were necropsied. Neoplasms were identified in six kangaroos, a prevalence rate of 21%. Neoplasms were the single leading cause of death in kangaroos during the study period. All six animals succumbed to or were euthanatized because of their tumors.
The mean age of the animals at the time of death was 11 years. All affected animals were female; however, the collection was managed to exhibit only females. Two oral squamous cell carcinomas, two mixed mammary gland adenocarcinomas, one multicentric T-cell lymphoma, and one pyloric submucosal lipoma were identified. This last mass led to gastric dilation and volvulus, and although decompression and surgical correction were successful, the kangaroo died five days later. Three of the six tumors were considered malignant and all three patients had developed metastases (Table 1).
Table 1. Summary of red kangaroo neoplasms identified at the Kansas City Zoo, 1992–2002
|
Case
|
Age
|
Neoplasm
|
Location(s)
|
|
1
|
11 years
|
Squamous cell carcinoma
|
Maxillary arcade
|
|
2
|
5 years
|
Multicentric T-cell lymphoma
|
Myocardium, liver, salivary gland, lymph nodes
|
|
3
|
13 years
|
Lipoma
|
Pyloric submucosa
|
|
4
|
14 years
|
Mixed mammary gland adenocarcinoma
|
Mammary glands, pulmonary tissue
|
|
5
|
10 years
|
Squamous cell carcinoma
|
Mandibular arcade, regional lymph node
|
|
6
|
14 years
|
Mixed mammary gland adenocarcinoma
|
Mammary glands, pulmonary tissue
|
A cause for the high frequency of neoplasms in red kangaroos in this population has not been identified, though neoplasia is generally more common in aged animals. Macropod neoplasia is uncommonly reported in the literature.1-4 In one 14-year review of pathology in Macropodidae, neoplasia was identified in only one of 314 necropsies performed across all species.1 Zoo veterinarians should consider neoplasia when presented with clinically ill, older red kangaroos.
Literature Cited
1. Griner LA. Pathology of Zoo Animals. Zoological Society of San Diego. 1983:270,315.
2. Kosanke SD, Feeback DL, Jensen JM. Oral squamous cell carcinoma in a giant red kangaroo. JAVMA. 1979;175(9):974–976.
3. Speare R, Banks D. A trichoepithelioma in a wild eastern grey kangaroo (Macropus giganteus). J Wildl Dis. 1987;23(3):508–509.
4. Wallach J, Boever WJ. Diseases of Exotic Animals. Philadelphia, PA: WB Saunders; 1983:600.