Gallbladder Agenesis in a Dog: Clinicopathological, Histopathology, and Computed Tomography Findings

Patent hepatic ciliated foregut remnant resulting in an umbilicobiliary sinus tract, with gallbladder agenesis, in an 8-wk-old male French Bulldog

Hepatic ciliated foregut remnants or cysts are congenital abnormalities resulting from retention of embryonic ciliated foregut within the liver. These structures are rarely reported in the human medical literature and have not been reported in the veterinary literature previously, to our knowledge. We describe here a case of an 8-wk-old male French Bulldog with a congenital patent hepatic ciliated foregut remnant resulting in an umbilicobiliary sinus tract. The dog also had concurrent gallbladder agenesis. The patient had yellow fluid discharging from the umbilicus, mimicking a patent urachus. Surgical exploration, removal, and histology provided a conclusive diagnosis of a hepatic foregut remnant and therapeutic resolution of the clinical signs. The histologic appearance of a hepatic foregut remnant is classical, namely a duct composed of 4 layers: an inner ciliated epithelial lining, loose connective tissue, smooth muscle, and a fibrous capsule.

Common bile duct perforation due to choledocholithiasis in a cat with gallbladder agenesis

Case summary

An 8-year-old neutered male domestic shorthair cat was presented for further investigation of anorexia, vomiting and lethargy. Abdominal ultrasonography and contrast-enhanced CT revealed choledocholithiasis with suspected bacterial peritonitis and non-visualisation of the gallbladder. During surgery, the common bile duct was noted to be perforated, and a cholelith was found in the abdominal cavity. No gallbladder was confirmed during surgery. Three months postoperatively, the cat underwent CT cholangiography and absence of the gallbladder with a vestigial duplicated gallbladder was diagnosed.

Relevance and novel information

Gallbladder agenesis is extremely rare in cats, with only one previous report, but several dogs have been diagnosed based on CT cholangiography and laparoscopy. This report describes gallbladder agenesis concurrent with choledocholithiasis in an adult cat and represents the first report of CT cholangiography in a cat with gallbladder agenesis.

A case of a congenital umbilicobiliary fistula associated with gallbladder agenesis in a dog

Congenital biliary tree malformations are rarely described in the veterinary field. A congenital umbilicobiliary fistula associated with gallbladder agenesis was reported here for the first time in a 1-year-old male French bulldog. After contrast study, abdominal ultrasound, and histopathology, we concluded that the umbilicobiliary fistula was an aberrant duct that originated directly from the expected location of the cystic duct and gallbladder. The clinical case was treated surgically through ligation and excision of the aberrant duct before entering the common bile duct. The recovery and long-term follow-up were uneventful. The pathophysiology of biliary congenital malformations is discussed, along with clinical considerations that should be considered in similar future cases.

Canine hepatobiliary anatomy, physiology and congenital disorders

The biliary system is an integral component of normal physiologic homeostasis and essential for survival. It acts as a conduit for the removal of detoxified and catabolised compounds as well as aids in fat digestion and absorption. Derangements in this system can have dangerous sequela that are associated with varying degrees of morbidity and mortality. Moreover, abnormalities in development of the biliary system can have varied and unpredictable changes on function and long-term outcome. The aims of this article were to review canine hepatobiliary anatomy, physiology and cholestasis as well as summarise congenital biliary disorders including human corollaries.