Breast Atypical Ductal Hyperplasia

**Semantic type:** Neoplastic Process

**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.

**Synonyms:** - ADH - ADH - Atypical Breast Ductal Hyperplasia - Atypical Ductal Breast Hyperplasia - Atypical Ductal Breast Hyperplasia - Atypical Ductal Hyperplasia of Breast - Atypical Ductal Hyperplasia of the Breast - DIN 1B - Ductal Intraepithelial Neoplasia, Grade 1B - atypical ductal breast hyperplasia - atypical ductal hyperplasia