Hepatic Biliary Adenofibroma: Histological Characteristics, Diagnostic Challenges, and Its Role as a Precursor to Intrahepatic Cholangiocarcinoma.

Hepatic biliary adenofibroma is an exceedingly rare biliary neoplasm that primarily affects adults. It typically presents as a solitary mass composed of low-grade microcystic and tubuloglandular bile duct structures, which are lined by low columnar to cuboidal non-mucin-producing biliary epithelium and supported by abundant fibrous stroma. Histologically, it resembles the Von Meyenburg complex but is much larger in size and often shows cytologic atypia. Although considered benign, emerging case studies and analyses suggest that biliary adenofibroma may serve as a precursor lesion to intrahepatic cholangiocarcinoma. However, its extreme rarity, coupled with an incompletely understood histogenesis, perpetuates diagnostic uncertainty and may lead to misclassification with other similar entities. This review consolidates the current understanding of the histopathological and molecular characteristics of biliary adenofibroma, highlights its differential diagnosis, explores its potential progression to cholangiocarcinoma, and discusses unresolved questions while proposing future research directions.