Anatomy of the hepatic hilar area: the plate system

To surgically manage hilar bile duct carcinoma successfully, it is important to be familiar with the principal anatomical variations of the biliary and vascular components of the plate system in the hepatic hilar area, because all the variations in the bile ducts and vessels occur in the plate system. The plate system consists of bile ducts and blood vessels surrounded by a sheath. There are three plates in the hilar area: the hilar plate, the cystic plate, and the umbilical plate. The bile duct and blood vessel branches penetrate the plate system and form Glisson's capsule in all segments of the liver, except for the medial segment. The right hepatic duct is usually (in 53%–72% of individuals) formed by the union of the anterior segmental duct and the posterior segmental duct in the hilar area. However, three other variations have been found in which these segmental ducts do not form the right hepatic duct. Few anatomical variations have been identified in the left hepatic duct, but confusion arises because of the variations in the medial segment ducts (B4) which join the left hepatic duct at different sites. In 35.5% of individuals they join the hepatic duct in the vicinity of the hilar confluence (type I B4 anatomy), and in 64.5% of individuals they join the left hepatic duct some distance away from the confluence (type II B4 anatomy). Because B4 is very close to the hilar confluence in type I, hilar bile duct carcinoma can easily invade B4 and, for that reason, for curative resection of hilar bile duct carcinoma, resection of S4a (the inferior part of the medial segment) should be considered along with the resection of extrahepatic bile duct and caudate lobe. Variations in the portal vein and hepatic artery are found in 16%–26% and 31%–33% of individuals, respectively. Because a considerable number of anatomical variations in the bile ducts and vessels persist in the hilar area, and the reported proportions of the different variations vary, it is necessary to have a good knowledge of the plate system and the variations in the bile ducts and blood vessels in the hilar area to perform safe and curative surgery for hilar bile duct carcinoma.     

Distributing pattern of the bile duct of the caudate lobe on computed tomography with drip infusion cholangiography and its surgical significance

BACKGROUND/AIMS: It is important to recognize the distribution of the bile ducts in the caudate lobe of the liver for the hepato-biliary surgery. To map the spatial relationship between the bile ducts and the liver parenchyma under physiological conditions, we performed an anatomical analysis of them using computed tomography combined with drip infusion cholangiography (DIC-CT). METHODOLOGY: We identified the bile ducts in the caudate lobe, which was divided into the Spiegel lobe, paracaval portion, and caudate process, with DIC-CT. We then investigated their number and confluence pattern in 132 patients without any abnormality in the hilar bile ducts. RESULTS: The mean number of the bile ducts in the caudate lobe was 2.68 per liver. In the Spiegel lobe, the branches drained into the left hepatic duct system in about 83%. The confluence of the paracaval branch was the left hepatic duct, right hepatic duct, and posterior segmental branch, all with the same frequency of approximately 30%. Almost all of the caudate process branches (92.4%) drained into the posterior segmental branch. CONCLUSIONS: DIC-CT is a useful method for the anatomical analysis of the intrahepatic bile ducts under physiological conditions, and we obtained novel and important findings for surgery.     

Radiological anatomy of the medial segmental bile duct of the liver assessed by CT cholangiography

BACKGROUND/AIMS: To analyze drainage areas and points of confluence of the medial segmental bile ducts of the liver, 72 patients with obstructive jaundice underwent computed tomography cholangiography. METHODOLOGY: We divided the medial segmental ducts into the following three subsegmental branches: B4a was defined as the inferior branch, B4b as the superior branch, and B4c as the dorsal branch. RESULTS: In 62 (86%) of the 72 patients, each B4a and B4b branches joined to form a single medial segmental duct, which joined the left hepatic duct in 25 patients (35%), the confluence of the lateral inferior (B3) and superior (B2) branches in 18 patients (25%), B3 in 15 patients (20%), the confluence of the right and left hepatic ducts in 4 patients (6%). In addition, these medial segmental ducts primarily entered the left hepatic duct in the final half of its length or more distant portion from the hepatic hilum in 43 (77%) of the 62 patients. CONCLUSIONS: Thus, in most cases the inferior area of the medial segment should be preserved when right-sided resection of the liver is indicated for hilar bile duct cancer.     

Preoperative cholangiography of the caudate lobe: Surgical anatomy and staging for biliary carcinoma

The biliary branches of the caudate lobe (B1) join the right hepatic duct, the left hepatic duct, the confluence of these ducts, and/or the right posterior segmental bile duct. Therefore, in the preoperative staging of biliary tract carcinoma it is important to delineate the anatomy of B1 and the extent of cancer spread into B1. Tube cholangiography through percutaneous transhepatic biliary drainage or selective cholangiography by percutaneous transhepatic cholangioscopy enables us to obtain fine images of B1. We have developed cholangiography in the cephalad anterior oblique position to visualize B1 more clearly and distinctly. Four separate types of biliary branches are identified in the caudate lobe: (1) A duct running from the cranial portion of the right caudate lobe along the inferior vena cava to the hepatic hilus (B1r); (2) a duct from the cranial portion of the left caudate lobe to the hepatic hilus (B1ls); (3) a duct from the left lateral part of the left caudate lobe to the hepatic hilus (B1li); and (4) a duct from the caudate process to the hepatic hilus (B1c). The findings of the root of B1 in resected patients with biliary tract carcinoma were classified into four groups: not stenotic, short segmental stenosis, long segmental stenosis, and poorly imaged. A study of 64 branches of B1 in 42 resected patients with biliary tract cancer revealed carcinoma invasion in or near the root of B1 in all patients with poorly imaged or long segmental stenosis of B1, and in 33% of those with short segmental stenosis of B1.     

Resection of an icteric type hepatoma with tumor thrombi filling the right posterior bile duct

A 67-year-old male with jaundice was found to have hepatocellular carcinoma in the right hepatic lobe and tumor thrombi in the common hepatic duct. Physicians initially considered the tumor unresectable, and treated the patient with transcatheter arterial infusion chemotherapy and biliary endoprosthesis. The patient developed a liver abscess after the second transcatheter arterial infusion, and the physicians consulted our department for another form of therapy. Percutaneous transhepatic biliary drainage was performed to relieve revived obstructive jaundice. Cholangiography revealed tumor thrombi extending through the right posterior segmental bile duct into the common hepatic duct. Most biliary branches of the caudate lobe joined with the left lateral posterior segmental branch. Arterial and portal venous branches of the caudate lobe were not involved. Right hepatic lobectomy and extrahepatic bile duct resection were performed 1 year after initial diagnosis. On histologic examination, the epithelium of the right posterior segmental bile duct, which was filled with the tumor thrombi, was not detected. The patient is alive without recurrence 24 months after surgery. Careful investigation of biliary branches of the caudate lobe on cholangiography is essential to determine the necessity of caudate lobectomy in patients with hepatocellular carcinoma and tumor thrombi filling the right posterior segmental bile duct.     

An unusual growth pattern of a mucin-producing intrahepatic cholangiocellular carcinoma involving the hepatic hilus.

The case of a mucin-producing intrahepatic cholangiocellular carcinoma in a 73 year-old-man is presented. A tumor originating in the right posterior inferior segment of the liver was found to be invading the right posterior and anterior bile ducts, and the hepatic hilus. Extensive superficial spread was observed in the entire posterior segmental bile duct extending to the hepatic hilus. Mucin produced and excreted by the tumor was retained in the common hepatic and common bile duct. The diagnosis in this case was suggested by percutaneous transhepatic aspiration of mucinous bile, and was confirmed by utilizing the techniques of ultrasonography, percutaneous transhepatic cholangiography, computed tomography and angiography. Curative surgery, which included right hepatic lobectomy with total caudate lobectomy and bile duct resection, was performed. Biliary continuity was maintained by left hepaticojejunostomy using a Roux-en-Y jejunal loop. The histological diagnosis was mucin-producing papillary adenocarcinoma originating in the right posterior inferior segment of the liver. Postoperative recovery was very good and the patient has now been enjoying a good active social life for the last 20 months with no signs of tumor recurrence. This case report discusses the unusual growth pattern of a mucin-producing intrahepatic cholangiocellular carcinoma involving the hepatic hilus, and suggests rational surgical treatment.     

Liver metastasis of rectal cancer with intraluminal growth in the extrahepatic bile duct

Metastatic liver tumors are considered to have a tendency for expansive growth and rarely invade the bile duct. We recently encountered a resected case of liver metastasis from rectal cancer with intraluminal growth in the extrahepatic bile duct with a successful left trisegmentectomy of the liver. A 54-year-old woman underwent a posterior total pelvic exenteration for advanced rectal cancer. Ultrasonography and computed tomography four months after the first operation demonstrated a solitary occupied lesion in the liver with dilation of the left hepatic duct. Endoscopic retrograde cholangiopancreatography disclosed a filling defect in the intra- to extrahepatic bile duct. Liver metastasis from rectal cancer with intraluminal growth in the bile duct was suspected despite a consideration of primary bile duct cancer. A left trisegmentectomy of the liver and resection of the extrahepatic bile duct with a right hepatojejunostomy were performed. The tumor had invaded the intrahepatic bile duct and had developed intraluminally in the extrahepatic bile duct. Tumor thrombi were microscopically found in the bile duct of the left caudal lobe. Liver metastasis arising from colorectal cancer with intraluminal growth in the bile duct is rare, however we encountered such a case with a successful resection involving a left trisegmentectomy of the liver.     

Variations of intrahepatic and proximal extrahepatic bile ducts

BACKGROUND/AIMS: The modern segmental concept of the liver with a segmental bile duct distribution is of practical importance for biliary specialists and should include information on variations of intrahepatic and extrahepatic bile ducts. The aim of this study was to find biliary variations, especially on a segmental and sectorial level, and to try to arrange them into types. METHODOLOGY: We analyzed 51 corrosion casts of the human liver, which enabled the three-dimensional study of extrahepatic, sectorial, segmental and subsegmental bile ducts, their variations in course and confluencing, and the relationship between the structures of the portal pedicle. RESULTS: The types of confluence and their frequency were determined separately for the left, right, right anterior sectorial, right posterior sectorial and common hepatic ducts. "Normal" left confluence was formed in 82% and three variations in 18%. "Normal" right confluence was formed in 75% and four variations in 25%. A complete ("normal") anterior sectorial duct was present in 35% and four variations in 65%. A complete ("normal") posterior sectorial duct was present in 61% and four variations in 39%. CONCLUSIONS: The study showed that the biliary tree variations are quite frequent, and therefore clinically important, and that they could be arranged into several types.     

Successful resection of cholangiocellular carcinoma with tumor thrombus in the main trunk of the portal vein

A space-occupying lesion in the right hepatic lobe, with dilated peripheral bile ducts, was observed by ultrasonography and computed tomography in a 50-year-old man with right upper quadrant abdominal pain. One month later, this lesion evidenced rapid growth and a tumor thrombus, which completely occluded the main trunk and the left primary branch of the portal vein, had developed. The tumor was diagnosed as a cholangiocellular carcinoma with an unusual pattern of intravascular extension. The primary tumor and the portal tumor thrombus were resected via a right hepatic trisegmentectomy combined with resection of the portal vein and extrahepatic bile duct, using a superior mesenteric vein—left femoral vein catheter bypass (SMV—FV bypass). The SMV—FV bypass was found to effectively reduce intraoperative hemorrhage.     

Small hepatocellular carcinoma presenting as intrabiliary pedunculated polyp and obstructive jaundice

A rare autopsy case of small hepatocellular carcinoma presenting as an intrabiliary pedunculated mass is reported. The patient, 60-year-old man, presented with obstructive jaundice and died 1 month later. At autopsy, an intrabiliary pedunculated tumor measuring 3.5 x 2.0 x 2.0 cm was found in the hepatic, right hepatic, and right posterior segmental bile ducts. The intraductal tumor was attached to the segmental bile ductal wall, where a tumor measuring 2.0 x 0.9 cm was found in the parenchyma. The parenchymal tumor was continuous with the intrabiliary mass. Histologically, the tumor was a hepatocellular carcinoma showing acidophilic granular cytoplasm with occasional hyaline globules and was structurally arranged in a vague trabecular pattern. Immunohistochemically, tumor cells were positive for alpha-fetoprotein and alpha 1-antitrypsin, but was negative for keratin. We present a brief review of the literature of such icteric hepatocellular carcinomas.     

Extended right hepatic lobectomy with resection of inferior vena cava and portal vein for intrahepatic cholangiocarcinoma

We report a case of intrahepatic cholangiocarcinoma treated by extended right lobectomy and resection of the inferior vena cava (IVC) and portal vein. A 53-year-old man was referred with elevated serum alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (γ-GTP) levels on April 23, 1999. He was not jaundiced and did not have any symptoms. Endoscopic retrograde cholangiopancreatography (ERCP) revealed irregular strictures in both the anterior and posterior segmental ducts. Contrast-enhanced computed tomography (CT) scan demonstrated a low-density tumor with an unclear margin in the right lobe of the liver. The patient underwent extended right hepatic lobectomy and total caudate lobectomy. Partial resection of the IVC (6 cm) was performed under total hepatic vascular exclusion. The main portal trunk and left portal vein were resected and reconstructed with an end-to-end anastomosis. Macroscopically, a 5.0 × 5.0 × 4.5-cm periductal infiltrating-type tumor occupied the right hepatic parenchyma along the posterior and anterior segmental ducts. Histological examination revealed moderately differentiated tubular adenocarcinoma with marked perineural invasion. Lymph node metastasis was observed in the hepatoduodenal ligament and posterior surface of the pancreatic head. The resected margins of the common bile duct and left hepatic duct were free of tumor. The patient's postoperative course was uneventful, and he was discharged from hospital on the 28th postoperative day. Nine months after the operation, he suddenly developed obstructive jaundice, and died with recurrent disease. This is the first reported case of intrahepatic cholangiocarcinoma treated with major hepatectomy and resection of the IVC and portal vein except ex situ procedure. This aggressive surgical approach may offer hope for patients with intrahepatic cholangiocarcinoma involving the IVC.     

A localized primary sclerosing cholangitis preoperatively diagnosed as hilar cholangiocarcinoma; report of a case

The authors report herein a case of primary sclerosing cholangitis localized to the hepatic hilum which occurred in a 67-year-old male. The direct cholangiography revealed bile duct stenosis from the common hepatic duct to bilateral hepatic ducts. We could not confirm bile duct malignancy, however, hilar cholangiocarcinoma was most suspicious. We performed right trisegmentectomy of the liver with caudate lobectomy and lymph node dissection 3 weeks after right portal embolization. Pathological findings confirmed localized primary sclerosing cholangitis. Surgical resection of the affected bile duct is most effective in localized primary sclerosing cholangitis, because the prognosis of the disease is poor and secondary carcinogenesis in primary sclerosing cholangitis has high incidence.     

Recurrent fibrolamellar hepatocellular carcinoma with biliary invasion: Successful resection

A jaundiced 17-year-old man was diagnosed as having a local recurrence of fibrolamellar hepatocellular carcinoma 2 years and 4 months after left hepatic trisegmentectomy with total caudate lobectomy had been performed. The patient had a tumor occupying the upper part of the extrahepatic and intrahepatic bile ducts. Complete resection of the recurrent tumor was carried out. The patient remains well 3 years after the second surgery. Fibrolamellar hepatocellular carcinoma, a rare type of liver cancer, is a well defined disease entity with distinct clinical and histopathological features and a favorable prognosis. The good prognosis seems to warrant aggressive surgical intervention in patients with recurrences. Therefore, additional surgery for tumor recurrence should be considered. To our knowledge, this is the first report of a case in which a recurrent tumor of fibrolamellar hepatocellular carcinoma invaded the entire bile duct wall was successfully resected.     

Benign biliary stricture associated with atherosclerosis

We report a case of benign bile duct stricture that could not be differentiated from intrahepatic bile duct carcinoma preoperatively. The patient was a 79-year-old man. Computed tomography showed dilatation of the intrahepatic bile duct in the left lobe. Direct cholangiography showed segmental stricture of the left bile duct. Angiography showed narrowing of the left hepatic artery. Although bile cytology did not show malignant cells, we suspected intrahepatic bile duct carcinoma preoperatively. We performed extended left hepatic lobectomy. Histopathologic examination of the resected duct also showed no malignant cells; fibrosis with infiltration by lymphocytes was seen at the bile duct stricture. In addition, the resected liver specimen showed sclerotic change in the intrahepatic arteries. The postoperative course was uneventful for more than 26 months, without recurrence or cholangitis. We encountered a very rare case of benign segmental bile duct stricture, which was difficult to differentiate from bile duct carcinoma. We think the biliary stricture was secondary to atherosclerosis which may have caused bile duct ischemia.     

Obstructive jaundice due to hepatobiliary cystadenoma or cystadenocarcinoma

INTRODUCTION Hepatobiliary cystadenomas (HBC) are rare neoplasms of the liver or extrahepatic bile ducts, accounting for less than 5% of all the cystdenomas found in the liver. These lesions are mainly seen in middle-aged females[1,2] and can show maligna…     

Intraductal oncocytic papillary neoplasm of the bile duct: the first case of peribiliary gland origin

We report herein the first case of intraductal oncocytic papillary neoplasm of the bile duct arising from a peribiliary gland of the left hepatic duct. The patient was a 63-year-old Japanese man. Radiological and cholangioscopic examinations revealed intraductal tumor of the left hepatic duct. After pathological diagnosis of adenocarcinoma by cholangioscopic biopsy, a surgical hepatobiliary resection was performed. Pathological examination revealed papillary tumor in the left hepatic duct. Histologically, the tumor was identified as papillary neoplasm comprising oncocytic cells and delicate fibrovascular cores. Interestingly, this tumor originated from the cystic space in the bile duct wall. This cystic space was histologically identified as a cystically dilated peribiliary gland. Carcinoma in situ was observed in this cystic peribiliary gland at the bottom of the tumor, but not on any areas of biliary epithelium. This case suggests that intraductal papillary neoplasm can arise from both biliary epithelium and peribiliary glands.     

Usefulness of laparoscopy and intraductal ultrasonography in a patient with isolated immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is often associated with type 1 autoimmune pancreatitis, and the frequency of isolated IgG4-SC seems to be quite low, making the diagnosis of isolated IgG4-SC challenging. A 63-year-old male was admitted to our hospital for frequent fever. Abdominal magnetic resonance cholangiopancreatography showed diffuse narrowing of the common bile duct and post-stenotic dilatation of the right posterior bile duct. Laboratory tests showed abnormalities in the levels of hepatobiliary enzymes and serum IgG4 levels. Endoscopic retrograde cholangiopancreatography showed diffuse narrowing of intrahepatic bile ducts and post-stenotic dilatation of the right posterior bile duct but no abnormalities in the pancreas. Intraductal ultrasonography showed symmetric circumferentially thickened walls of both narrowed and non-narrowed common bile ducts. Histologic examination of the common bile duct mucosa showed infiltration of IgG4-positive plasma cells. Laparoscopic observations showed discoloration with red lobular markings and multiple small depressed lesions. Liver histology showed mild cholangitis with infiltration of IgG4-positive plasma cells around the bile ducts. From these findings, the patient was diagnosed with isolated IgG4-SC. After treatment with a steroid, bile duct dilatations improved. Laparoscopy and intraductal ultrasonography were useful to diagnose isolated IgG4-SC.     

Surgical anatomy of the medial segment (S4) of the liver with special reference to bile ducts and vessels

BACKGROUND/AIMS: Resection of the inferior area of the medial segment (S4a) plus S5 with preservation of the superior area of the medial segment (S4b) is being performed to manage hilar bile duct carcinoma and pT2 type gallbladder carcinoma, and thus, attention has been focused on the surgical anatomy of the medial segment of the liver to identify the specific vessels and bile ducts of the areas of that segment to be resected and to be preserved. METHODOLOGY: Anatomical study of the bile duct, portal vein, middle hepatic vein, and middle hepatic artery to the medial segment branches of the liver (S4) was performed in a total of 171 specimens comprised of 71 adult cadavers, and 100 liver casts. RESULTS: 1) Two main types of bile duct branches of the medial segment (B4) were recognized. Type I included the branches which joined to the left hepatic duct on the hilar duct side (35.5%), and type II included the branches that joined on the peripheral side (54.6%). Several subtypes were also found in both types. The B2-B3 confluence was mostly on the left (41.7%) or posterior (42.7%) to the umbilical portion (UP) of the portal vein, and to the right of the UP (hilar side) in only 15.6%. 2) The portal vein of the medial segment branches (P4): P4a branched from the right angle and upper right border of the UP in every specimen. The most common morphology was 1 large and 2-3 small branches (41%). P4b was almost always found to branch posterior to the UP and lower than P4a, and the most common morphology was 1 large and 0-1 small branches (57.8%). 3) The middle hepatic vein: In 83.2% a common trunk was observed at the confluence with the inferior vena cava, and 8 types of the middle hepatic vein were recognized. 4) The middle hepatic artery: It arose from the left hepatic artery in 61.5%, from of the right hepatic artery in 27.5%, from the proper hepatic artery in 5.5%, and from both the left and the right hepatic artery in 5.5%. CONCLUSIONS: The detailed vascular and bile duct anatomy of S4 is described. This study should be helpful in identifying the specific vessels and bile ducts of the areas of the medial segment to be resected and to be preserved, thereby facilitating resection of the medial segment.     

Intrahepatic segmental bile duct patterns in hepatolithiasis: a comparative cholangiographic study between Taiwan and Japan

Background/Purpose. We analyzed confluence patterns of intrahepatic segmental bile ducts, seeking to relate hepato-lithiasis to anatomic variation. The comparative study was completed patients with hepatolithiasis in Taiwan and Japan. Methods. Direct cholangiography was performed in 103 hepatolithiasis patients in Taiwan and 77 in Japan. Segmental ducts patterns were classified as type I, normal configuration; type II, “triad” confluence; type III, posterior segmental duct joining left hepatic duct; or type IV, distal confluence of the right posterior segmental duct. Results. Taiwanese patients had only calcium bilirubinate or black stones, and were mostly female. As overall analysis, types I, II, III, and IV were found in 61, 26, 13, and 3 patients, respectively. In Japanese, types I, II, III, and IV were found in 52, 10, 13, and 2, respectively. There was no difference between the two institutes. Since no patients in Taiwan had cholesterol calculi, Japanese patients were reanalyzed including only 58 patients with calcium bilirubinate or black stones. Differences in those populations remained insignificant. Conclusion. Anatomic variations in segmental ducts apparently do not contribute to pathogenesis of hepatolithiasis.     

Hepatectomy for cholangiocarcinoma complicated with right umbilical portion: anomalous configuration of the intrahepatic biliary tree

The right umbilical portion (right‐sided round ligament) has been discussed as an intrahepatic portal venous anomaly associated with “left‐sided gallbladder” in several reports. We treated two patients with right umbilical portion (RUP) associated with cholangiocarcinoma. Left hepatectomies were performed, preserving the residual hepatic blood flow and biliary continuity. From our experience in these patients we propose the presence of anomalous configuration of the intrahepatic biliary tree in RUP, because both patients showed medial segmental bile ducts ramified from the right and left hepatic ducts. In general, although the medial segmental bile duct ramified from the left, we surmised that this abnormal bilateral drainage pattern may not be a rare phenomenon in RUP. Special attention may be required to focus on the anatomy of the portal tributaries and biliary ramifications in RUP.