atypical ductal hyperplasia atypical ductal hyperplasia atypical ductal hyperplasia of breast DIN 1B atypical ductal hyperplasia of the breast MedDRA:10068781 atypical breast ductal hyperplasia Atypical ductal hyperplasia is the term used for a benign lesion of the breast that indicates an increased risk of breast cancer. Atypical ductal hyperplasia is an atypical proliferative lesion that falls in between the continuum from normal hyperplasia to low grade ductal carcinoma in situ. atypical ductal breast hyperplasia UMLS:C1332347 NCIt:C8436 Laura Huerta ductal intraepithelial neoplasia, Grade 1B SNOMEDCT:264505003 https://doi.org/10.1155/2012/297832 ductal breast hyperplasia