Cystic pancreatitis in a Shetland pony mare diagnosed on ultrasound and computed tomography

Summary A Shetland pony mare presented for investigation of colic of 6 h duration. On examination, she was tachycardic with moderate abdominal pain. Initial abdominal ultrasonography showed a large volume of swirling echogenic free fluid within the peritoneal cavity, which was confirmed to be sanguinous on abdominocentesis. Blood analysis showed a reduced haematocrit (14%), hypoproteinaemia (36 g/L) and increased lactate in addition to other mild abnormalities. She received a blood transfusion, and her haematological and biochemical parameters and comfort improved during her stay at the clinic. Repeat abdominal ultrasonography identified a large mass in the right side of the abdomen, adjacent to the right kidney, right dorsal colon, duodenum and right liver lobe. Computed tomographic examination of the abdomen performed under general anaesthesia confirmed this mass to be the markedly enlarged pancreas with cystic regions within it, and small gas foci within one of the cystic areas, consistent with abscessated pancreatitis. Ultrasound‐guided biopsy of the mass was performed, and histopathology showed chronic suppurative and fibrosing pancreatitis. On further serum biochemical analysis, amylase activity was normal, but lipase was increased (30 u/L). The mare received a prolonged, tapering course of oral prednisolone. The pancreas could not be identified on repeat abdominal ultrasound 30 months post‐initial presentation, and serial serum biochemical analysis has shown the lipase concentration to have reduced to normal limits. The mare remains systemically well at 4 years post‐presentation. Equine pancreatic pathology is rare, with few reports of pancreatitis, pancreatic neoplasia and involvement in systemic disease processes. To the authors' knowledge, this is the first report on the use of CT and CT angiography to aid the diagnosis of equine pancreatitis, and the case highlights the utility of CT in the investigation of abdominal disease in small equine patients.