A case of cholecystohepatic duct with atrophic common hepatic duct

Abstract

Background

Cholecystohepatic ducts are rare congenital variants of the biliary tree.

Case outline

An 81-year-old woman presented with biliary colic and elevated liver function tests. An ERCP demonstrated a common bile duct stone and stricture of the common hepatic duct. An operative cholangiogram demonstrated an atrophic common hepatic duct and retrograde filling of the gallbladder through a large cholecystoheptic duct. The patient had a cholecystectomy and reconstructive cholecystohepatic duct jejunostomy.

Discussion

This case demonstrates a rare congenital anomaly where the gallbladder fills retrograde during an intraoperative cholangiogram despite clipping of the cystic duct. The major path of biliary drainage was through a large cholecystoheptic duct similar to a gallbladder interposition; however, the common hepatic duct was still present but atrophic. This anomaly has not been described previously.

Introduction

Anatomical variation of the biliary tree occurs with sufficient frequency to be of concern to the surgeon operating in this area. Several persistent fetal connections have been described between the liver and either the gallbladder or the extrahepatic biliary ducts. These pericholecystic anomalies include the subvesical ducts of Luschka, cholecystohepatic ducts and gallbladder interposition.

True cholecystohepatic connections are rare. We report a case of a woman with a presumed hepatic duct stricture who was found on intraoperative cholangiography to have an atrophic common hepatic duct and a large cholecystohepatic duct. The major pathway of biliary drainage was through the gallbladder.

Case report

A healthy 81-year-old woman presented with a 3-week history of intermittent epigastric pain, radiating to both shoulder blades, nausea and vomiting. Liver function tests showed an obstructive pattern, and an ultrasound scan of the biliary tree showed cholelithiasis and choledocholithiasis.

The patient was transferred to a tertiary care hospital where she underwent an endoscopic cholangiogram (ERCP) and sphincterotomy with successful extraction of common bile duct stones. The ERCP also showed that there was narrowing of the common hepatic duct, and an attempt to pass a guide wire through this area was unsuccessful. After ERCP, the patient was pain-free and was discharged home. Further investigation of this ‘stricture’ included a magnetic resonance cholangiogram (MRCP), which showed mild intrahepatic biliary dilatation but could not further delineate the biliary anatomy. A computed tomography (CT) scan did not show any evidence of a mass in this area.

The patient returned for laparoscopic cholecystectomy, with intraoperative cholangiography planned to investigate further the ‘stricture’ and rule out a cholangiocarcinoma. After clip occlusion of the cystic duct at the gallbladder neck, the fluorocholangiogram first showed a dilated distal common bile duct, then filling of a tortuous atrophic ‘common hepatic duct’. The intrahepatic ducts then filled, with retrograde opacification of the gallbladder through a large cholecystohepatic duct (Figure 1). The right anterior and posterior sectoral ducts had separate connections, one above and one below the take-off of the atrophic common hepatic duct.

Figure 1. .

Fluoroscopic cholangiography through the proximal cystic duct demonstrates a dilated common bile duct with sequential filling of a small tortuous common hepatic duct (arrow) and then the intrahepatic biliary tree; a large cholecystohepatic duct then fills the gallbladder behind the occluding clip.

The patient was converted to an open operation. During the removal of the gallbladder a 1-cm diameter bile duct was found to enter the gallbladder approximately 2 cm above the cystic duct. It was decided to reconstruct this large cholecystohepatic duct, as this was the major pathway for biliary drainage; a Roux-en-Y hepaticojejunostomy to this duct was performed. Post-operatively the patient made a satisfactory recovery, with no complications and specifically no postoperative bile leakage.

Discussion

Anatomic variability of the biliary tree is well described ¹,². Several anatomic studies have described accessory bile ducts as persistent fetal connections between the liver and the gallbladder or the extrahepatic bile duct system, with an overall incidence quoted as 9–28% ³. These accessory ducts are thought to arise as a result of disordered biliary tract embryology. During the fourth week of gestation the hepatic diverticulum arises ventrally from the distal foregut and divides into two parts. The hepatic primordium develops cranially, forming interlacing cords of hepatocytes and the intrahepatic biliary tree. The gallbladder and cystic duct develop caudally, with a confluence of fetal hepatic ducts opening into the proximal cystic duct, to form the common hepatic duct. The extrahepatic biliary tree is initially occluded with endodermal cells, but is later recanalized ⁴,⁵.

The anomaly we present, that of cholecystohepatic duct, is thought to arise when there is a persistent connection between the fetal hepatic ducts and the gallbladder, with failure of complete recanalization of the common hepatic duct resulting in its atresia ⁴ or, in our case, a small atrophic duct. The existence and incidence of ‘pericholecystic’ bile ducts is controversial, and the nomenclature used to describe variations in this area is confusing and inconsistent in the literature ⁶. It is common for separate bile ducts to drain variable portions of the right liver and to join the main biliary tract. Specifically, the right anterior and posterior sectors often have separate ducts ⁷, as was the case in our patient. These mostly represent normal variations ⁸ and have a reported incidence of 15–20% ⁹.

These normal variations are not to be confused with the pericholecystic bile duct variations discussed below. These include subvesical ducts (of Luschka) running in the gallbladder plate but not draining into the gallbladder; cholecystohepatic ducts, draining variable portions of the right lobe directly into the gallbladder lumen, and lastly, gallbladder interposition. In 1863 Luschka ¹⁰ first described small bile ducts lying in the gallbladder fossa, either as blind ducts emerging from the right lobe of the liver, or ducts running subserosally to join one of the main biliary channels later. He stated that he did not believe that these ducts entered the gallbladder lumen, thereby differing from true cholecystohepatic ducts ¹¹. Most authors describe these subvesical ducts as 1–2 mm in diameter, draining a variably sized subsegment of the right posterior sector and entering the right hepatic duct, the common hepatic duct or rarely the cystic duct. Their incidence has ranged in several studies from 12% to 50% ¹². In support of Luschka's theory, Michels ¹³ dissected 500 cadavers and failed to find one case of a subvesical duct communicating with the gallbladder lumen, as did Healy and Schroy in their corrosion cast study ¹⁴. McQuillan and co-workers ¹⁵ found that the subvesical duct most commonly lay in the centre of the gallbladder bed; the other frequent site was the lateral peritoneal reflection. Of note is that in none of their post-mortem studies was the duct visible before dissection of the gallbladder from its bed.

Cystohepatic ducts are defined as those draining a variable portion of the right lobe into the cystic duct. Some authors use this term to include connections to the gallbladder (cholecystohepatic ducts) ¹⁶. True cholecystohepatic ducts are rare ²,³,⁴,⁶,¹⁷. Several studies have shown combined incidences of cystohepatic and cholecystohepatic ducts of between 0.2% and 2.3% ¹⁶. A large series based on operative and cholangiographic findings demonstrated that the overall incidence of cystohepatic and cholecystohepatic ducts was 0.85% (12 cases in 1410 cholecystectomies). However, only one of the 12 cases was an actual cholecystohepatic duct ¹⁶.

Cystohepatic and cholecystohepatic ducts may occur in the presence of normal common hepatic and common bile ducts ². As noted above, the hepatic territory drained by these ducts is variable. In the series of Champetier and colleagues ¹⁶ the majority were segmental or subsegmental ducts. Two of the cystohepatic ducts acted as right hepatic ducts, draining segments 5, 6, 7 and 8 into the cystic duct. Drainage of the right, left, or both, hepatic ducts into the gallbladder is infrequent ²,¹⁸. Complete interposition of the gallbladder has been reported in a few individuals ¹⁷,¹⁹. In these cases both the right and left hepatic ducts drain directly into the gallbladder, either separately or as one main duct, with associated absence of the common hepatic and cystic duct. The sole pathway for biliary drainage is therefore via the gallbladder.

We believe our case to be unique, in that it almost represents gallbladder interposition; the large cholecystohepatic duct was the major drainage conduit for the right and left hepatic ducts. However, in addition our patient had a narrow, tortuous common hepatic duct remnant. Kihne et al.⁴ reported a similar, but not identical, case in which a cholecystohepatic duct drained the intrahepatic junction of the right and left hepatic ducts through the gallbladder and through a small stenosed cystic duct into the distal common duct.

The importance of these variations in biliary anatomy lies in their vulnerable position during cholecystectomy ³. Only occasionally may they be seen by preoperative endoscopic cholangiography or MRCP. Most of these ducts are too small to be delineated ⁶, and even a large anatomic variation may not be appreciated, as in our case. Therefore, these anomalies are rarely identified before operation. Accidental damage to a duct draining an extensive hepatic territory should be repaired immediately, by either direct suturing over a T-tube or reconstruction with a Roux-en-Y hepaticojejunostomy, as in this case.