Abstract:

Objective

To analyze the clinical characteristics and treatment strategies of intraductal papillary neoplasm of the bile duct （IPNB） through a large sample case analysis.

Methods

A retrospective analysis was conducted of the data of 94 patients with IPNB， admitted to two large medical centers in China from September 2006 to October 2022.

Results

（1） Only 21.3% （20/94） of IPNB patients were correctly diagnosed before surgery， and 38.3% （36/94） were misdiagnosed as cholangiocarcinoma.Compared to other preoperative examinations， MRI/MRCP had a higher diagnostic accuracy of 24.1% （13/54）.The typical imaging manifestation was bile duct dilation combined with intraductal tumor， and the newly recognized finding of specific characteristic as bird's beak like stenosis at the end of the common bile duct might be an important feature.（2） 38 cases of tumors were located in the left liver， accounting for 40.4%， which is the most common location.Pathologically， IPNB with low-grade intraepithelial neoplasia were 15 cases （16.0%），high-grade intraepithelial neoplasia were 33 cases （35.1%）， and invasive cancer were 46 cases （48.9%）.The first two were defined as benign tumors， while the latter was defined as malignant tumors.The location of the tumor and whether it secretes mucus were not related to the malignancy of IPNB.（3） All patients underwent surgical resection， including 72 cases of liver resection， 9 cases of extrahepatic bile duct resection combined with biliary intestinal anastomosis， and 13 cases of Whipple.The R0 resection rate was 95.7%， with 61 cases undergoing lymph node dissection and the lymph node positivity rate was 3.3% （2/61）.（4） The postoperative 1-， 3-， 5-， and 10-year survival rates were 91.1%， 82.0%， 73.5%， and 44.0%， respectively.Univariate analysis showed that weight loss， CA125 elevation， tumor malignancy were related to long-term prognosis of patients （P＜0.05）.Multivariate analysis showed that tumor malignancy alone was an independent risk factor for long-term prognosis （OR=2.479， 95% CI： 1.127-5.453， P=0.024）.Compared with benign IPNB，malignant IPNB had shorter survival time， with median survival time of 14.3 and 8.4 years， respectively（P＜0.05）.

Conclusions

IPNB is difficult to be diagnosed correctly before surgery， with nearly half being invasive cancer and a low lymph node positivity rate.Radical resection surgery should clarify the extent of the lesion before surgery， and if necessary， intraoperative cholangioscopy needs to be performed.In order to attain radical resection， the cutting edge of the bile duct should be provided for intraoperative frozen biopsy.Selective adjuvant treatment can be performed after surgery.The long-term prognosis of IPNB is good， and tumor malignancy is an independent risk factor.

Key words: Bile duct neoplasms, Intraductal papillary neoplasm of the bile duct, Diagnosis, Lymph node metastasis, Surgical principles, Prognosis