Intraductal tubulopapillary neoplasm of the bile duct: potential origin from peribiliary cysts

We report two patients with unique biliary tumors histologically similar to pancreatic intraductal tubulopapillary neoplasm (ITPN). One patient underwent right hepatectomy for a partly cystic mass in the hepatic hilum. The other patient had liver transplantation for cryptogenic cirrhosis and multiple hilar cysts detected in the explanted liver, some obliterated by papillary nodules. Histologically both tumors consisted of intracystic non-invasive and well differentiated adenocarcinoma with a papillary and tubular architecture. Associated cysts were peribiliary cysts partly lined by carcinoma cells that were continuous with the intracystic papillotubular masses. Both tumors shared the same immunophenotype: K7(+)/K20(-)/MUC1(+)/MUC2(-)/MUC5AC(-)/MUC6(+). Genetic analysis of KRAS and BRAF revealed wild type genotypes. These pathological and genetic features are similar to those of pancreatic ITPNs. This report suggested that ITPNs may rarely develop in the bile duct seemingly in association with peribiliary cysts.     

Intraductal papillary neoplasm of the bile duct,gastric type,arising in the intrapancreatic common bile duct could progress to colloid carcinoma: report of a case

Intraductal papillary neoplasm of the bile duct (IPNB) exists in a pathway of multistep-carcinogenesis toward cholangiocarcinoma. Four subtypes are observed in IPNB, pancreatobiliary type, intestinal type, gastric type, and oncocytic type, similarly to the corresponding disease in the pancreas, intraductal papillary mucinous neoplasm (IPMN). IPNB can present with or without macroscopically visible mucin secretion. IPNB usually progresses to tubular adenocarcinoma. However, there are a limited number of well-described cases of gastric-type IPNB progressing not to tubular adenocarcinoma but to colloid carcinoma. Herein, we present a case of an 82-year-old female patient with gastric-type IPNB in the intrapancreatic common bile duct without macroscopically visible mucin secretion, which progressed to colloid carcinoma. As IPNB, especially without visible mucin secretion, is considered to be a heterogeneous group of diseases, such an unexpected association could occur.     

Proposal of histological criteria for intraepithelial atypical/proliferative biliary epithelial lesions of the bile duct in hepatolithiasis with respect to cholangiocarcinoma: preliminary report based on interobserver agreement

Biliary lining epithelia of the bile ducts in biliary diseases are known to have intraepithelial atypical/proliferative lesions related to the development of cholangiocarcinoma. The purpose of the present study was to determine the histological criteria for these lesions based on interobserver agreement. Digital images of 30 intraepithelial atypical/proliferative lesions in the stone-containing intrahepatic bile ducts of hepatolithiasis (30 cases) were sent to 10 pathologists. At first, 10 pathologists made a diagnosis (either of reactive/regenerative change, low-grade or high-grade biliary intraepithelial neoplasia (BilIN-1 and BilIN-2), or in situ carcinoma (BilIN-3)) based on their own criteria. The histological criteria for these four lesions were then determined, and the digital images of the same lesions with proposed criteria were re-distributed. Interobserver agreement on these four lesions was slightly improved (kappa = 0.44, first diagnosis; 0.49, second diagnosis) and intraobserver agreement was 'almost perfect' (kappa = 0.82 at both first and second diagnosis). Interobserver agreement between BilIN-1 and BilIN-2 and that between BilIN-2 and BilIN-3 were 'moderate', although the agreement between regenerative/reactive change and BilIN-1 was 'fair'. In this report, we propose histological criteria for reactive/regenerative change, BilIN-1, BilIN-2 and BilIN-3. Improvement of interobserver agreement suggests their applicability in diagnostic and research fields.