Bladder teratoma in a maned wolf (Chrysocyon brachyurus)

BACKGROUND: Teratomas are germ cell tumors, comprised of a mixture of tissue types and with tissue foreign to their site of origin. CASE DESCRIPTION: A 5.5-year-old intact female maned wolf (Chrysocyon brachyurus) was treated for recurrent stranguria and suspected cystitis. Due to lack of resolution, the wolf was anesthetized for further evaluation. The urinary bladder was firm on palpation, with a markedly thickened wall and no observable lumen on ultrasound. Neoplastic infiltration was suspected on double contrast cystogram and confirmed via surgical exploration. The lesion was inoperable and the wolf was euthanized. Gross necropsy revealed two poorly distinguished masses infiltrating the urinary bladder dorsally and caudoventrally, with minimal remaining lumen. Histopathologic examination of the bladder and associated masses revealed a neoplasm comprised of multiple tissue types. Vascular invasion was noted. CONCLUSION: The neoplasm was diagnosed as an extragonadal teratoma. Few extragonadal teratomas have been described and this is the first report of a teratoma originating in the urinary bladder of a non-human species.