NCI Definition: A neoplastic process that arises from the terminal ductal lobular unit of the breast parenchyma. It is usually solitary and confined to a single lobular unit. It is characterized by the presence of a monomorphic epithelial proliferation in a cribriform, micropapillary, or solid growth pattern. Focal architectural features of low grade ductal carcinoma in situ are present. There is an increased risk for development of invasive breast carcinoma. [1]

Disease Details

DIN 1B, Atypical Breast Ductal Hyperplasia, Ductal Intraepithelial Neoplasia, Grade 1B, ADH, atypical ductal hyperplasia
Precancerous Condition


1. National Cancer Institute. NCI Thesaurus Version 18.11d. https://ncit.nci.nih.gov/ncitbrowser/ [2018-08-28]. [2018-09-21].

2. The AACR Project GENIE Consortium. AACR Project GENIE: powering precision medicine through an international consortium. Cancer Discovery. 2017;7(8):818-831. Dataset Version 8. This dataset does not represent the totality of the genetic landscape; see paper for more information.

3. All assertions and clinical trial landscape data are curated from primary sources. You can read more about the curation process here.