Extrahepatic Bile Duct Biliary Intraepithelial Neoplasia

**Semantic type:** Neoplastic Process

**Definition:** A neoplastic, non-invasive lesion that affects the extrahepatic bile duct epithelium. It is characterized by the presence of atypical epithelial cells with an increased nuclear/cytoplasmic ratio, nuclear hyperchromasia, and loss of nuclear polarity.

**Synonyms:** - Extrahepatic Bile Duct BilIN - Extrahepatic Bile Duct Dysplasia