Reporting a Case on Congenital Agenesis of the Gallbladder with the Hypogenetic Cystic Duct Definitely Diagnosed by Peroral Cholangioscopy

Congenital agenesis of the gallbladder (CAGB) is a rare congenital anomaly, which is, in adults
serendipitously detected at autopsy or exploratory laparotomy in most cases. A 59-year-old Japanese
female presented with a few-day history of abdominal pain, nausea, vomiting, icterus, and low-grade
fever. Her past and family histories were non-contributory. Laboratory data showed elevated serum
hepatic and pancreatic enzymes, hyperbilirubinemia, and leukocytosis. Computed tomography (CT)
demonstrated the dilated biliary tree obstructed by a stone in the distal part and the swollen pancreas
with the enhanced peripancreatic adipose tissue. No entopic or ectopic gallbladder was detected by
ultrasonography (US), CT, or magnetic resonance cholangiopancreatography (MRCP). The papilla of
Vater was patent-orificed. Though failed to visualize the gallbladder, endoscopic retrograde
cholangiography (ERC) showed a stone in the distal and a short, thin, blind tube arising from the mid
extrahepatic biliary tree. She underwent endoscopic sphincterotomy (EST) and choledocholithotomy
under the preoperative diagnosis of congenital agenesis of the gallbladder (CAGB) with the
hypogenetic cystic duct complicated with choledocholithiasis triggering acute cholangitis and
pancreatitis. Peroral cholangioscopy revealed the tube to be a crescent-folded cul-de-sac running
parallel with and draining into the common hepatic duct, the vestige of the abortive primordium which
should have developed into the full-fledged cystic duct and gallbladder, confirming the diagnosis. She
has kept an uneventful post-operative course. This is the fifth case of CAGB with the hypogenetic
cystic duct and the first in the world, in which the diagnosis was established by peroral findings.
Emphasized are the crucial role of peroral cholangioscopy and ERC and the importance of awareness
of the anomaly to obviate unnecessary, potentially dangerous exploration through the non-natural
orifices in quest of the phantom gallbladder. This report emphasizes the importance of awareness of
CAGB and highlights the crucial role of peroral cholangioscopy in diagnosing the anomaly and
consequently obviating unnecessary, potentially dangerous exploration through the non-natural
orifices in quest of the phantom gallbladder.