Breast Columnar Cell Hyperplasia with Atypia

**Semantic type:** Neoplastic Process

**Definition:** A columnar cell lesion characterized by the presence of enlarged terminal ductal lobular units with dilated acini. The acini are lined by more than two layers of columnar epithelial cells. Cytologic atypia is present. Prominent apical cytoplasmic snouts and intraluminal secretions are also present.

**Synonyms:** - Columnar Cell Hyperplasia of Breast with Atypia - Columnar Cell Hyperplasia of the Breast with Atypia