A captive-born, 5.5-year-old, female maned wolf (Chrysocyon brachyurus) was treated with antimicrobials for two bouts of stranguria due to suspected cystitis. Treatment did not result in resolution, so the animal was anesthetized for further evaluation. On physical examination, the bladder was extremely firm, and abdominal ultrasound showed marked thickening of the urinary bladder wall with no observable lumen. Neoplastic invasion of the bladder was suspected on double-contrast cystogram and confirmed by surgical exploration. As the mass encompassed most of the bladder, it was considered inoperable, and the wolf was euthanized.
Gross necropsy revealed a firm, white mass involving 80% of the luminal bladder surface, and a cerebriform mass extending into the bladder lumen. Histopathologic examination of the bladder and associated masses revealed a neoplasm comprised of multiple tissue types, including chondroid, bone, neural, and ring cells, as well as varying epithelial forms. Other features included multifocal necrosis and vascular invasion. The bladder mass was diagnosed as a malignant extragonadal teratoma.
Few extragonadal teratomas have been described in animal species. This is the first reported case of a teratoma originating at the urinary bladder in any nonhuman species.
The authors wish to thank the animal care staff of the Endangered Wolf Center and the staff of the Saint Louis Zoo’s Department of Animal Health for their care and dedication to this animal.