Development of extrahepatic bile ducts and mechanisms of tumorigenesis: Lessons from mouse models

Perihilar Cholangiocarcinoma Originating in Peribiliary Glands: Insights from a Case without Precancerous Lesions

BACKGROUND Recent studies have shown that peribiliary glands may be the potential cell origin of cholangiocarcinoma, and that precancerous lesions such as biliary intraepithelial neoplasms and intraductal papillary neoplasms of the bile duct may arise from these peribiliary glands. However, whether and how these precancerous lesions progress to cholangiocarcinoma is controversial. CASE REPORT Herein, an autopsy case of perihilar cholangiocarcinoma, exclusively periductal-infiltrating, is reported. Since repeated transpapillary biopsies and cytology showed no carcinoma cells, the patient was treated for sclerosing cholangitis until death. The findings at cholelithiasis treatment 1 year earlier had not aroused suspicion of the presence of precancerous lesions. The changes in the spread of bile duct stenoses on cholangiography and the unique findings at autopsy, namely (i) the distribution of cancer growing locally within the peribiliary gland compartment without invading the bile duct mucosa and (ii) the existence of in situ-like carcinoma cells replacing the epithelium of the peribiliary glands throughout the extrahepatic bile duct, suggested that cholangiocarcinoma arose from the peribiliary glands in the hilum without a detectable precancerous lesion and then spread to the lower end of the common bile duct via the peribiliary gland network. CONCLUSIONS This case report may help further our understanding of the natural history of cholangiocarcinoma and provide clues about cholangiocarcinogenesis and progression. In addition, histological and cytological diagnosis could be theoretically difficult by sampling tissue from the bile duct lumen in cholangiocarcinoma, as in this case.

Biliary stem cells in health and cholangiopathies and cholangiocarcinoma

PURPOSE OF REVIEW

This review discusses evidence regarding progenitor populations of the biliary tree in the tissue regeneration and homeostasis, and the pathobiology of cholangiopathies and malignancies.

RECENT FINDINGS

In embryogenesis biliary multipotent progenitor subpopulation contributes cells not only to the pancreas and gall bladder but also to the liver. Cells equipped with a constellation of markers suggestive of the primitive endodermal phenotype exist in the peribiliary glands, the bile duct glands, of the intra- and extrahepatic bile ducts. These cells are able to be isolated and cultured easily, which demonstrates the persistence of a stable phenotype during in vitro expansion, the ability to self-renew in vitro, and the ability to differentiate between hepatocyte and biliary and pancreatic islet fates.

SUMMARY

In normal human livers, stem/progenitors cells are mostly restricted in two distinct niches, which are the bile ductules/canals of Hering and the peribiliary glands (PBGs) present inside the wall of large intrahepatic bile ducts. The existence of a network of stem/progenitor cell niches within the liver and along the entire biliary tree inform a patho-biological-based translational approach to biliary diseases and cholangiocarcinoma since it poses the basis to understand biliary regeneration after extensive or chronic injuries and progression to fibrosis and cancer.

Biliary atresia: the development, pathological features, and classification of the bile duct

Biliary atresia is an occlusive biliary disease involving intrahepatic and extrahepatic bile ducts. Its etiology and pathogenesis are unclear. There are many manifestations of bile duct involvement in biliary atresia, but little is known about its occurrence and development. In addition, different classification methods have been proposed in different periods of biliary atresia, each with its advantages and disadvantages. The combined application of biliary atresia classification will help to improve the survival rate of patients with native liver. Therefore, this article reviews the development, pathological features, and classification of intrahepatic and extrahepatic bile ducts in biliary atresia, to provide a reference for the study of the pathogenesis and the choice of treatment methods.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.