Carlos R. Sanchez1, DVM, MSc (WAH); Randi Drees2, DrMedVet, DACVR, DECVDI; Jonathan Dunnum3, PhD; Itzel Yañez Muñoz4, MVZ, MC; Patricia M. Gaffney5, DVM, MPVM, DACVP; Michael M. Garner6, DVM, DACVP; Michael J. Kinsel7, DVM, DACVP
The Mexican gray wolf (Canis lupus baileyi) is the rarest, southernmost, and most genetically distinct subspecies of the North American gray wolves.6 It is also the smallest subspecies of the gray wolf and one of the most endangered canids in the world. Since the early 2000s at least 14 clinical cases of nasal carcinoma have been described in the captive population of Mexican wolves in the United States and in Mexico. Although cancer represents only 3.3% of the mortality of the registered Mexican wolf population, the majority of these neoplasms have been categorized as sinonasal carcinomas (Gaffney, Garner, unpublished data).7 Preliminary studies suggest that, as in dogs, a genetic component is involved in the carcinogenesis of this neoplasm.7 Advanced imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) are routinely used for the diagnosis of nasal tumors in dogs.1-5 Because most nasal tumors involve bony structures (including nasal turbinates and sinuses), CT exams are more commonly used to assess the extent of the nasal disease as well as to aid in differentiating between neoplastic and non-neoplastic processes. In addition, CT allows exact disease localization and staging, biopsy guidance, and treatment planning.1,5 Mexican wolves housed at the Brookfield Zoo as well as archived specimens (heads and skulls) from deceased Mexican wolves, were examined using CT to identify changes indicative of nasal disease and determine prevalence of nasal carcinoma on this species.
The authors thank the veterinary technician staff at the Chicago Zoological Society and John Pauley, CVT, in particular, for their assistance with the CT scans. We also thank VIZUA™ for the 3D renderings of the CT scans.
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6. Heritage Park Zoological Sanctuary. Official Homepage of the Mexican Wolf Species Survival Plan. mexicanwolves.heritageparkzoo.org/. Accessed April 2012.
7. Yañez I. Determinacion de alteraciones cromosomicas y genéticas presentes en distintas neoplasias del lobo Mexicano (Canis lupus baileyi). Power point presentation. Mexican wolf SSP annual meeting. South Salem, NY. 2010.