Choledochal cyst with secondary cholangitis, choledochitis, duodenal papillitis, and pancreatitis in a young domestic shorthair cat.

Choledochal cysts, congenital segmental dilations of the common bile duct, have been reported in few cats, and histologic characterization is lacking. A 20-mo-old spayed female domestic shorthair cat was presented because of vomiting and weight loss. There was progressive elevation of liver enzyme activity (ALT > ALP, GGT) and hyperbilirubinemia. Diagnostic imaging identified focal cystic dilation of the common bile duct, dilation and tortuosity of adjacent hepatic ducts, and a prominent duodenal papilla. A choledochal cyst was suspected, and the animal was euthanized. On postmortem examination, there was a 2-cm, firm, thickened, cystic dilation of the common bile duct, patent with adjacent ducts. Histologically, the cyst wall was expanded by fibroblasts, collagen, and lymphoplasmacytic inflammation. Adjacent bile ducts were markedly dilated and tortuous, with lymphoplasmacytic inflammation and papillary mucosal hyperplasia that extended to the major duodenal papilla. There was chronic neutrophilic cholangitis, suggesting bacterial infection and/or disturbed bile drainage, extrahepatic obstruction, and lymphoplasmacytic pancreatitis with ductular metaplasia. Prominent lymphoid follicles within biliary ducts and duodenum suggested chronic antigenic stimulation. Choledochal cysts can be associated with chronic neutrophilic cholangitis, extrahepatic obstruction, choledochitis, duodenal papillitis, and pancreatitis, and should be a differential for increased hepatic enzymes and hyperbilirubinemia in young cats.

Suspected choledochal cyst in a domestic shorthair cat.

A 9-year-old female neutered domestic shorthair cat was presented with a history of polyphagia, weight loss and inappropriate urination. Clinical examination revealed jaundice and a mid-cranial abdominal mass. Further investigations revealed a large extra-hepatic cyst originating from the biliary tract (choledochal cyst). Concurrent chronic, active neutrophilic cholangitis and chronic lymphoplasmacytic pancreatitis were also noted. Surgical drainage, subtotal resection and omentalisation of the cyst, along with supportive medical management, were successful in relieving the clinical signs.

Cyst of the common bile duct in a cat.

A cyst of the common bile duct (CBD) is reported in a 9-year-old cat that presented with a 1-week history of anorexia, weight loss and vomiting. Diagnosis was established by ultrasound examination and laparotomy, and was ultimately confirmed by histological analysis. Chronic cholangitis and an Escherichia coli species were detected concurrently according to the histopathological findings and bile culture, respectively. The case was managed by suturing the borders of the ostium of the cyst over a stent, using a temporary cholecystostomy tube and antibiotic therapy. At 7 months following the surgery, the cat was in excellent physical condition with no clinical evidence of recurrence of cholangitis or of the cyst after ultrasonographic evaluation. According to the human literature, cysts of the CBD require treatment because of their common association with cholangitis, pancreatitis, and cystic rupture. We were unable to confirm a link between the cyst and cholangitis in this case. It is possible that detection of this anomaly was an incidental finding unrelated to bacterbilia. Histological examination of cyst tissue is mandatory for a definitive diagnosis and to differentiate it from neoplasia. This is the first description of a cyst of the CBD in the cat.