Clinical and pathologic features of proximal biliary strictures masquerading as hilar cholangiocarcinoma

BACKGROUND: Nontraumatic inflammatory hilar strictures are uncommon, but are known to mimic malignancy. This study examines the clinical and pathologic features of benign idiopathic strictures. STUDY DESIGN: Patients without a history of trauma or earlier biliary operation treated for benign strictures were identified. Clinical information was obtained from the medical record and all resected specimens were reexamined. RESULTS: From January 1992 to July 2003, 275 patients with proximal biliary strictures were referred. Among these, 22 patients had a final histologic diagnosis of benign stricture, despite a suspected preoperative diagnosis of malignancy. All 22 patients underwent resection of the extrahepatic biliary tree, which in 10 patients was combined with en bloc partial hepatectomy. Histologic reexamination identified five different benign processes: lymphoplasmacytic sclerosing pancreatitis and cholangitis, primary sclerosing cholangitis, granulomatous disease, nonspecific fibrosis/inflammation, and stone disease. Major postoperative morbidity occurred in 6 (26%) patients but none died. No preoperative clinical or radiographic features were identified that could reliably distinguish patients with benign strictures from those with cancer. CONCLUSIONS: "Malignant masquerade" of the proximal bile duct results from several different underlying conditions, and differentiating benign strictures from cancer remains problematic. The treatment approach should continue to be resection for presumed malignancy.     

Surgical treatment of choledochal cysts

Biliary cystic disease is uncommon in Asia and very rare in Europe and the Americas. Patients with biliary cysts may present as infants, children, or adults. When patients present as adults, they are more likely to have stones in the gallbladder, common duct, or intrahepatic ducts and to present with biliary colic, acute cholecystitis, cholangitis, or gallstone pancreatitis. With increasing age at presentation, the risks of intrahepatic strictures and stones, segmented hepatic atrophy/hypertrophy, secondary biliary cirrhosis, portal hypertension, and biliary malignancy all increase significantly. Factors to be considered when performing surgery on patients with biliary cystic disease include: (1) age, (2) presenting symptoms, (3) cyst type, (4) associated biliary stones, (5) prior biliary surgery, (6) intrahepatic strictures, (7) hepatic atrophy/hypertrophy, (8) biliary cirrhosis, (9) portal hypertension, and (10) associated biliary malignancy. In general, regardless of age, presenting symptoms, biliary stones, prior surgery or other secondary problems, surgery should include cholecystectomy and excision of extrahepatic cyst(s). With respect to the distal bile duct, the surgical principle should be excision of a portion of the intrapancreatic bile duct with care to not injure the pancreatic duct or a long common channel. Resection of the pancreatic head should be reserved for patients with an established malignancy. With respect to the intrahepatic ducts, surgery should be individualized depending on whether (1) both lobes are involved, (2) strictures and stones are present, (3) cirrhosis has developed, or (4) an associated malignancy is localized or metastatic. When the liver is not cirrhotic, hepatic parenchyma should be preserved even when strictures and stones are present. If cirrhosis is advanced, hepatic transplantation may be indicated, but this sequence of events is unusual. If a malignancy has developed, oncologic principles should be followed. Whenever possible, resection of a localized tumor including adjacent hepatic parenchyma and regional lymph nodes should be performed.     

Bile obstruction in hepatocellular carcinoma--visualization by endoscopic retrograde cholangiography. A case report

Extrahepatic biliary obstruction is a rare presentation in hepatocellular carcinoma (HCC), only 31 cases having been reported in the literature. We describe a patient with extrahepatic biliary obstruction in whom endoscopic retrograde cholangiography was suggestive of cholangiocarcinoma. Laparotomy and subsequent investigation, however, confirmed HCC metastasizing to the common hepatic duct. The cholangiographic appearance of HCC involving extrahepatic bile ducts is emphasized and features differentiating it from cholangiocarcinoma are highlighted. Even though extrahepatic biliary obstruction in HCC is rare, this disorder should be considered in the differential diagnosis of obstructive biliary tract disease.     

Xanthogranulomatous Inflammatory Strictures of Extrahepatic Biliary Tract: Presentation and Surgical Management

Background Xanthogranulomatous cholecystitis (XGC) is a benign, invasive variant of chronic cholecystitis. Invasion of common bile duct (CBD), termed as xanthogranulomatous choledochitis, may mimic malignancy. We describe clinico-pathological features and management of xanthogranulomatous inflammatory biliary strictures. Methods A review of a prospectively maintained database for XGC was performed. Results Out of 6,150 cholecystectomies performed, 620 patients had XGC (10% incidence). Four patients had biliary strictures with xanthogranulomatous choledochitis on final histology. All four patients presented with jaundice and history of cholangitis. Ultrasonography revealed gallstones and thick-walled gallbladder in all. Two patients had hilar strictures: one had mid-CBD stricture and one had a lower-CBD stricture with a dilated pancreatic duct. In all four patients, preoperative diagnosis of malignancy was entertained. Three patients underwent resection—CBD excision for mid-CBD stricture, pancreaticoduodenectomy for lower-end stricture, and right hepatectomy for hilar stricture with atrophy-hypertrophy complex. One patient with unresectable hilar stricture underwent hepaticojejunostomy. Conclusion Xanthogranulomatous choledochitis may be considered as one of the differential diagnosis in patients with biliary stricture especially in a geographical area with a high incidence of XGC, when a patient harbors gall stones and had thick-walled gall bladder on imaging. This stricture can be found anywhere in the biliary tree from hepatic hilum to the lower end. However, preoperative imaging and cytology are unreliable both in confirming the diagnosis or ruling out malignancy. Therefore, resection of the stricture should be attempted wherever feasible.     

Hilar cholangiocarcinoma—surgical anatomy and curative resection

We have studied the surgical anatomy of the intrahepatic bile duct, hepatic hilus, and caudate lobe based on intraoperative findings and selective cholangiography of surgical patients and resected specimens, and have established the cholangiographic anatomy of the intrahepatic subsegmental bile duct. Thorough knowledge of the three-dimensional anatomy of the subsegmental bile duct, hepatic hilus, and caudate lobe is indispensable for curative surgery of hilar cholangiocarcinoma. We designed and actually performed 15 kinds of hepatic segmentectomies with caudate lobectomy and extrahepatic bile buct resection in 100 consecutive patients, with curative resection being possible in 82 patients. Postoperative survival after curative resection of hilar cholangiocarcinoma was better than expected, and the 5-year survival rates for all 82 patients with curative resection and for 55 patients with curative surgery without portal vein resection were 31% and 43%, respectively. Hepatic segmentectomy with caudate lobectomy and extrahepatic bile duct resection should be designed not only in accordance with the preoperative diagnosis of tumor extension into the intrahepatic bile ducts but also so that curative surgery for advanced hilar cholangiocarcinoma can be performed.     

Incidence of benign lesions in patients resected for suspicious hilar obstruction

BACKGROUND: The differentiation between benign and malignant strictures at the hepatic hilum is difficult. The aim of this study was to assess the clinical and radiographical features of hilar lesions in a series of patients resected for a presumed cholangiocarcinoma. METHODS: Of 132 consecutive patients undergoing resection for a suspicious lesion at the hepatic hilum, 20 (15 per cent) had a histopathologically proven benign tumour, diagnosed as chronic fibrosing or erosive inflammation, sclerosing cholangitis, or a granular cell tumour. All medical files and radiological examinations of the patients were reassessed. RESULTS: Clinical symptoms were considered suspicious in 16 of 19 patients. At ultrasonography only one of 16 patients had an unsuspicious examination. In 14 of 18 patients cholangiographic images were considered suspicious. Overall reassessment confirmed a suspicious lesion in all 20 patients. CONCLUSION: Because of the limitations of current diagnostic tools, a false-positive preoperative diagnosis of malignancy resulted in a 15 per cent resection rate of benign lesions in this series of suspicious hilar strictures.     

Extensive hilar bile duct resection using a transhepatic approach for patients with hepatic hilar bile duct diseases

BACKGROUND: Extensive hilar bile duct resection beyond the second- or third-order intrahepatic biliary radicals is usually required for patients with hilar cholangiocarcinoma as well as those with benign inflammatory stricture. Most hilar cholangiocarcinoma is resected with combined major hepatectomy to obtain free surgical margins. The purpose of this study was to show the surgical procedure and the usefulness of extensive hilar bile duct resection using a transhepatic approach for patients with hilar bile duct diseases. METHODS: Five patients with hepatic hilar bile duct disease and who were unfit for major hepatectomy for several reasons underwent extensive hilar bile duct resection by way of a transhepatic approach. Four of the patients had hilar bile duct cancer, including 1 with mucous-producing bile duct cancer of low-grade malignancy and 1 with a postsurgical benign bile duct stricture. RESULTS: After extensive hilar bile duct resection, bile duct stumps ranged in number from 3 to 7 mm (mean 4.4). Surgical margins at bile duct stump were free of cancer in all 4 cancer patients. The long-term outcomes were as follows: 3 patients are alive at the time of publication, and 2 patients have died. CONCLUSIONS: A transhepatic approach may be useful when performing extensive hilar bile duct resection bile duct stricture of biliary disease at the hepatic hilus, especially in high-risk patients who are unfit for major hepatectomy as well as in those having benign bile duct stricture and low-grade malignancy.     

Adenomyoma of the Common Hepatic Duct Mimicking Bile Duct Cancer: Report of a Case

We report an unusual case of adenomyoma of the common hepatic duct mimicking bile duct cancer. A 50-year-old woman was referred to our hospital for the investigation of general fatigue. Laboratory data showed abnormal liver test results and computed tomography showed a mass lesion in the hepatic hilum and dilatation of the intrahepatic bile ducts. These findings led to a preoperative diagnosis of hilar bile duct carcinoma, and we performed a left lobectomy with resection of the extrahepatic bile duct. Macroscopically, an elevated lesion was found in the common hepatic duct, which was confirmed histologically to be an adenomyoma. Bile duct strictures are rarely caused by benign tumors of the biliary tract, such as adenomyoma. Surgical resection of the bile duct should be considered for all bile duct strictures because it is often difficult to differentiate malignant from benign lesions in this location preoperatively, and malignant cells may be present in the lesion.     

Benign strictures of the bile ducts. Significance of adequate bile duct drainage for the prognosis and course of this disease

Ninety-five patients with benign biliary strictures are presented in this study. All underwent reconstructive biliary surgery, either for proximal biliary strictures (Group A; 38 patients) or for distal biliary strictures (Group B; 57 patients). The type of bypass was individualized according to each patient's mechanical and anatomical characteristics as were assessed in our cholangiographic findings. For group A we used either a proximal to the stricture intrahepatic cholangiojejunostomy between Roux-en-Y jejunal loop and the main right or left hepatic ducts or multiple intrahepatic cholangiojejunostomies between segmental hepatic ducts and a Roux-en-Y jejunal loop. For Group B we chose between a choledocho- or hepaticoduodenostomy and a choledocho- or hepaticojejunostomy. There were three deaths due to sepsis, one in patients of group A and two among those of group B. Long-term results were satisfactory. None of our patients during a mean six year follow-up underwent further surgery for reasons related with either his/her operation or disease.     

Long-term follow-up after bilioenteric anastomosis for benign bile duct stricture.

OBJECTIVE: The authors provide a prospective evaluation of long-term results after bilioenteric anastomoses for benign biliary stricture. SUMMARY BACKGROUND DATA: With the advent of laparoscopic techniques, the frequency of bile duct injury after operation has increased. Reports on the operative management of these injuries have not provided long-term follow-up. Over a similar period, reports of both endoscopic and invasive radiographic methods as primary treatment for bile duct stricture have compared success rates to antiquated surgical reports. METHODS: A protocol whereby preoperative radiographic (e.g., cholangiogram, computed tomographic scan, ultrasound), biochemical (e.g., alkaline phosphatase, and total bilirubin), and clinical evaluation was combined with ongoing postoperative evaluation and follow-up at approximately 6-month intervals. A total of 111 patients were evaluated from 1985 to 1995. Patients were categorized in three groups: 1) those with postoperative injuries during open and laparoscopic gallbladder surgery (31 patients), 2) those undergoing operation for pain associated with chronic pancreatitis who have distal common bile duct stenoses (64 patients), and 3) those with nonchronic pancreatitis-associated benign bile duct strictures (16 patients). RESULTS: Mean follow-up was 60 months. Overall preoperative alkaline phosphatase was 640 units/L with a range of 280 to 1860 units/L. All patients had abnormally elevated alkaline phosphatase. Only 3 of 111 patients have had mild persistent elevation after operation. Clinical jaundice, present in 49 of 111 patients, was resolved uniformly by operative decompression. Total bilirubin was elevated abnormally in 56 of 111 patients and also was uniformly corrected by operation. CONCLUSIONS: These data support the careful combined use of endoscopy, invasive radiology, and surgery in the management of benign strictures of the biliary tree. These data further suggest a success rate for surgical management that, over long-term follow-up, appears to exceed that found using alternative measures. Alternative methods should measure their success rates against success rates currently achieved by operative management.     

Differential Diagnosis of Stenosing Lesions at the Hepatic Hilus

A significant number of stenosing lesions at the hepatic hilus represent benign disease rather than hilar cholangiocarcinoma. It is unclear, however, which perioperative investigations are useful for defining benign lesions in this location. A series of 49 consecutive patients who presented with obstructive jaundice due to a stenosing lesion at the hepatic hilus were investigated by documenting elevated plasma bilirubin levels, the presence of weight loss, and elevated carcinoembryonic antigen (CEA) and Ca 19-9 concentrations. Radiologic investigations included direct cholangiography, transabdominal ultrasonography, computed tomographic (CT) scans and magnetic resonance imaging (MRI). A tissue diagnosis was obtained in all patients, and the preoperative investigations were reviewed to assess their accuracy for predicting malignancy. The final tissue diagnosis was a benign lesion in 12 patients (benign idiopathic strictures 10, choledocholithiasis 2). Among the 37 patients who presented with a malignant lesion, 2 had metastatic colorectal cancer, 7 had gallbladder cancer, and 28 had hilar cholangiocarcinoma. Of the 12 patients with benign lesions, 4 (33%) had elevated tumor markers (CEA and CA 19-9), 12 (100%) had cholangiograms suspicious for malignancy, and 9 (75%) had CT and MRI features consistent with a malignant diagnosis. Thus among patients presenting with hilar strictures approximately one-fifth are due to nonmalignant causes, but the preoperative diagnosis is difficult and resection remains the most reliable way to rule out malignancy in this site.     

胆管癌的磁共振诊断与误漏诊原因分析

目的总结胆管癌MR征像,提高MR对胆管癌的诊断与鉴别诊断的准确性。方法本组收集1996年1月～2005年12月,经MRI及MRC诊断为胆管癌或MRI诊断胆管炎但临床怀疑胆管癌67例。分析MRI和MRCP的影像学表现和诊断,并与手术病理结果进行对照。结果术前MR诊断正确的56例,漏诊8例,误诊3例。肝门区胆管癌31例;胆总管区胆管癌24例。病理学表现为结节型18例,肿块型21例,浸润型13例,乳头型14例。结论胆管癌的MRI表现与生长方式有关,MRCP诊断胆管梗阻定位准确率高,仔细观察各种征像并结合临床,可提高胆管癌诊断的准确性。     

肝门部胆管癌外科治疗的争议与进展

肝门部胆管癌（HCCA）主要发生在肝总管和左右肝管及其汇合部,其约占胆管癌的50.0%～70.0%,是胆道系统常见的恶性肿瘤,且其发病率亚洲最高。目前,手术是治疗HCCA的唯一有效途径。HCCA因早期症状缺乏或不典型,往往患者出现黄疸或者明显腹痛等临床症状,已到进展期才能明确诊断,且其解剖位置特殊、复杂,肿瘤具有沿胆管生长及浸润性生长的生物学特性,其根治性手术切除率及长期生存率均较低。HCCA的外科治疗已取得了较大的进展,但仍然是外科医生所面临的挑战之一。在外科治疗方面,目前还存在许多争议,新的争议点也在不断出现,譬如是否需要实施术前胆道引流及方式、剩余肝体积不足的解决、肝切除的范围、淋巴清扫范围、联合血管切除及肝移植的价值、微创手术应用等。笔者基于当前最新发表文献探讨这些争议,以期对HCCA正确认识和理解,规范化HCCA的治疗,改善患者预后。     

The long-term outcome of hepaticojejunostomy in the treatment of benign bile duct strictures.

OBJECTIVE: The authors review the treatment and outcome of patients with benign bile duct strictures who underwent biliary enteric repair. SUMMARY BACKGROUND DATA: The authors conducted a retrospective review of all clinical records of patients referred for treatment of benign bile duct strictures caused by surgery, trauma, or common bile duct lithiasis or choledochal cyst. The authors performed univariate and multivariate analyses of clinical and pathologic factors in relation to patient outcome and survivals. METHODS: Eighty-four patients with documented benign bile duct strictures underwent hepaticojejunostomy, choledochojejunostomy, and intrahepatic cholangiojejunostomy during a 15-year period (January 1975 to December 1989). Morbidity, mortality, and patient survival rates were measured. RESULTS: Early and late outcomes correlated neither with demographic and clinical features at presentation nor with etiologic or pathologic characteristics of the stricture. Best results correlated with high biliary enteric anastomoses and degree of common bile duct dilatation independently of bile duct stricture location. CONCLUSIONS: High biliary enteric anastomosis provides a safe, durable, and highly effective solution to the problem of benign strictures of the bile duct. Transanastomotic tube stenting is unnecessary. Endoscopic and percutaneous transhepatic dilatation seems more appropriate for the treatment of patients in poor condition and those with anastomotic strictures.     

Benign hilar biliary strictures stented with metallic stents can be resected by using an oncologic approach

BACKGROUND: Biliary metallic stents (MS) are being used increasingly to treat patients with malignant bile duct strictures. In patients with benign strictures, MS are contraindicated because these stents are considered unremovable. The aim of this study was to report the operative treatment of patients with benign biliary strictures at the hepatic confluence stented with MS. METHODS: Five patients with a benign hilar stenosis stented with MS underwent liver resection with biliodigestive anastomoses. The operations were designed to remove all MS by a combined biliary and hepatic resection. RESULTS: After preoperative portal vein embolization in 2 patients and percutaneous biliary drainage in 2 others, all underwent a major hepatectomy with resection of the biliary confluence and a biliodigestive anastomosis. One patient also underwent resection of the portal vein bifurcation that could not be freed from the bile duct wall. Four patients experienced postoperative complications. With a mean follow-up of 37 months (range, 31-47 months), all patients have remained symptom-free. CONCLUSIONS: Operative treatment of benign hilar strictures in patients with MS is possible if they are managed similarly as patients with hilar malignancies. This demanding procedure should be considered an alternative to liver transplantation for benign strictures treated with MS, but the procedure requires expertise in advanced hepatic resections.     

Granular cell tumor at the hepatic duct confluence mimicking Klatskin tumor. A report of two cases and a review of the literature

BACKGROUND: Granular cell tumors are rare tumors most often located in the oral cavity, skin or subcutaneous tissue. The occurrence of this tumor in the biliary tree is extremely rare. METHODS: Two patients are described presenting with biliary obstruction due to a tumor at the hepatic duct confluence. One patient is a 38-year-old white male with concomitant cutaneous granular cell tumors, and the other a 50-year-old white female. RESULTS: Hilar excision was performed in both patients. Histopathology of the tumors revealed a proliferation of cells with granular cytoplasm, diagnosed as granular cell tumor. CONCLUSION: At preoperative examination, hilar granular cell tumors are difficult to differentiate from cholangiocarcinoma, sclerosing cholangitis or more common benign biliary tumors. Treatment consists of surgical excision after which prognosis is favorable.     

Ischemic-type biliary lesions in liver transplant recipients: evaluation with magnetic resonance cholangiography

We assessed the diagnostic value of magnetic resonance cholangiography (MRC) when evaluating ischemic-type biliary lesions in the follow-up of liver transplant patients. We retrospectively reviewed magnetic resonance imaging and MRC of 28 liver transplant recipients with ischemic changes of the biliary tree. The MR examinations were performed at 1.5 T. After the acquisition of axial T1w and T2w sequences, MRC involved a coronal respiratory-triggered, fat-suppressed, two-dimensional, thin-slab, heavily T2w fast spin-echo sequence, and/or a coronal breath-hold, thin- and thick-slab, single-shot T2w sequence. Eleven patients underwent either surgical reconstruction of the biliary system (n = 4) or liver retransplantation (n = 7); the pathologic specimens were employed as standard of reference. The final diagnosis was obtained through direct cholangiography in the remaining cases. Without knowledge of the surgical, pathologic, and cholangiographic findings, two experienced investigators evaluated in conference the MR images to determine the presence of biliary tract abnormalities. MRC demonstrated strictures involving the hepatic bifurcation and the extrahepatic bile duct of the graft in 26 patients; a concomitant thickening of the biliary wall was described in 18 out of these 26 subjects. MRC also showed sludge or stones formation in the donor common bile duct in 16 out of these patients. In conclusion, MRC allows noninvasive, reliable, assessment of ischemic-type biliary lesions in liver transplant recipients.     

Reoperative surgery for postcholecystectomy bile duct injuries

BACKGROUND: Surgical repair for a postcholecystectomy bile duct injury can be complicated by the development of an anastomotic stricture which necessitates re-intervention. The authors reviewed their experience with patients requiring re-operation after unsuccessful surgical repair of the bile duct injury, to analyze the possible causes of the failure of the operative procedure and the long-term outcome following revisional surgery. METHODS: Retrospective analysis of the records of 41 patients referred to a tertiary care center for the management of recurrent stricture following surgical repair performed for a postcholecystectomy bile duct injury. RESULTS: Before referral, 69 operative procedures had been performed on these 41 patients. Factors likely to be associated with increased chances of failure of the biliary reconstructive procedures included presentation with cholangitis after the biliary injury, no cholangiographic study before the surgical repair and surgical intervention within 3 weeks of the injury. Thirty-seven (90%) patients were found to have strictures at or above the level of confluence of right and left hepatic ducts, while at the time of the index repair only 12 (29%) patients had an injury at that level. Revisional surgery in all the patients was a Roux-en-Y hepaticojejunostomy. One patient died, 2 patients with multiple previous operations developed recurrence and needed intervention again. Over a mean follow-up period of 4.2 years, 90% patients had a satisfactory outcome. CONCLUSION: Development of recurrent stricture following surgical repair of a postcholecystectomy biliary injury can be related to the technique and timing of the surgical procedure, the complication may therefore be avoidable in some patients. In experienced hands the results of revisional surgery are good but are adversely affected as the number of previous repairs increases.     

Anatomic variants of the biliary tree with MR Cholangiography: feasibility and surgical applications

PURPOSE: To assess the usefulness of MR Cholangiography for evaluation of anatomic variants of the biliary tree before biliary surgery. MATERIALS AND METHODS: Our study group consisted of 45 consecutive patients (29 males, 16 females; mean age 57 years), who were referred for MR evaluation of malignant (n=26) and benign (n=19) cholangiopancreatic diseases. MR Cholangiography studies were independently reviewed by two radiologists. RESULTS: Anatomic variants of the biliary tree were observed in 9 patients (20%); 6 variants involved the biliary confluence and 4 the cystic duct (one patient had both). Anatomic variants involved principally the right posterior duct: 1 (2,2%) drainage of right posterior duct into left hepatic duct; 2 (4,4%) triple confluence of right posterior duct, right anterior duct, and left hepatic duct, and 3 (6,6%) aberrant drainage of right posterior duct into common hepatic duct. Observed cystic duct anomalies included: 2 (7,44%) low insertion of the cystic duct into the common hepatic duct and 3 (11,1%) medial insertion of the cystic duct into the common hepatic duct. CONCLUSION: MR Cholangiography accurately shows anatomic variants of the biliary tree. Noninvasive preoperative evaluation of the biliary anatomy may be important for the detection of anatomic variants that may increase the complexity of hepatic surgical procedures and biliary interventions.     

经内镜胆管内支架置入术对良恶性胆管梗阻的临床应用

目的探讨经内镜胆管内支架置入术对各种良恶性胆管梗阻的治疗效果。方法95例良恶性胆管梗阻病人先行内镜逆行胰胆管造影（ERCP）检查,确定胆管梗阻病变部位和性质后,再决定使用内镜下塑料胆道支架引流（ERBD）和内镜下金属胆道支架引流（EMBE）。结果95例患者中92例插管成功,成功率96.84%（92/95）。针对良性胆管梗阻行ERBD 28例,主要见于胆总管结石;针对恶性胆管梗阻行ERBD 44例,行EMBE 20例,主要见于胰头癌、胆管癌、壶腹癌、原发性肝癌及肝门、肝内转移压迫胆管,所有病例均在引流后总胆红素及直接胆红素明显下降。结论：经内镜下胆管内支架引流术的应用愈来愈广泛,其操作安全而有效,特别是对各种良恶性病变引起的胆管梗阻起了关键性的治疗作用。