Gastrointestinal small-cell lymphoma with gall bladder involvement in a cat

A 13-year-old female spayed domestic shorthair cat presented for investigation of decreased appetite and increased serum liver enzyme concentrations. An abdominal ultrasound revealed multiple sessile hyperechoic structures along the luminal aspect of the gall bladder wall and a mildly enlarged liver with hyperechoic nodules. Cholecystectomy was performed and biopsies were obtained by laparotomy. Histopathologic examination with immunohistochemistry was consistent with a diagnosis of small-cell lymphoma of T cells within the gall bladder, liver and small intestine. Clonality testing confirmed the diagnosis. The cat remains clinically stable 23 months after institution of treatment with prednisolone, chlorambucil and ursodeoxycholic acid. This is the first report of small-cell lymphoma in the gall bladder of a cat.