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

Atypical Breast Ductal Hyperplasia, Ductal Intraepithelial Neoplasia, Grade 1B, atypical ductal hyperplasia, DIN 1B, ADH
Intraductal Proliferative Lesion of the Breast


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 6. 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.