An adult female North American river otter (Lontra canadensis) presented with multiple intrathoracic masses identified histologically as squamous cell carcinoma. Immunohistochemical staining patterns for high- molecular-weight keratin, p40, p63, calretinin, and TTF-1, along with the gross and histologic findings, indicated a primary pleural squamous cell carcinoma as the most likely diagnosis. 

Van de Velde, N., Demetrik, D.J., and Duignan, P.J. 2019. Primary pleural squamous cell carcinoma in a free-ranging River otter (Lontra canadensis). Journal of Wildlife Diseases DOI: 10.7589/2018-07-181.