URINARY BLADDER TRANSITIONAL CELL CARCINOMA AND CARCINOMATOSIS IN A LINNAEUS'S TWO-TOED SLOTH, CHOLOEPUS DIDACTYLUS

Abstract A 19-yr-old female Linnaeus's two-toed sloth (Choloepus didactylus) with a history of urinary incontinence, ascites, and behavioral changes was euthanized after diagnostic imaging revealed a large bladder mass. On gross necropsy, the sloth had a severely thickened bladder mucosa, partial urinary obstruction, and nonseptic exudate in the peritoneal cavity. Histopathology showed a malignant and highly invasive transitional cell (urothelial) carcinoma with transmural and intra-abdominal invasion and diffuse carcinomatosis. Immunohistochemistry for expression of pancytokeratin (AE1/AE3), cytokeratin 7 (CK7), cytokeratin 20 (CK20), and uroplakin III was performed to confirm the diagnosis of transitional cell carcinoma. Neoplastic cells had a strong cytoplasmic immunoreactivity with the antipancytokeratin antibody clone AE1/AE3, which was consistent with a neoplasm of epithelial origin. Neoplastic cells were negative for expression of CK20. This is the first detailed report describing the antemortem di...