NCIthesaurus intraductal breast benign neoplasm breast intraductal proliferative lesion UMLS_CUI:C1334631 disease_ontology DOID:6839 Intraductal Proliferative Lesion NCI:C27942 An intraductal breast benign neoplasm that is characterized by an increase in the number of cells perpendicular to the basement membrane resulting in total alteration and distension of the normal unit structure of the breast. It is confined to the duct-lobular system, originates from the terminal duct-lobular unit and displays different cytological and architectural patterns of proliferation.