Colonic papillary adenocarcinoma in a crab-eating fox (Cerdocyon thous): Anatomopathological and immunohistochemical features

Abstract

A captive 17-year-old male crab-eating fox (Cerdocyon thous) presenting clinical signs of hyporexia and constipation for two weeks was found dead. On autopsy, a large and firm mass expanding the large intestine wall and totally obstructing the colon lumen was identified. Histopathology revealed a non-encapsulated poorly demarcated adenocarcinoma composed of cuboidal to pseudostratified columnar epithelium forming papillary projections of variable sizes. The cytoplasm of the neoplastic cells was immunopositive for CK7 and PAN-CK, but negative for VIM and CK20. Immunohistochemistry revealed an immunophenotype different from the enteric adenocarcinomas reported in humans and domestic dogs. This is the first case report of colonic papillary adenocarcinoma in a crab-eating fox.