hyperplasia columnar cell hyperplasia of the breast MEDGEN:310623 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. Prominent apical cytoplasmic snouts are present. Secretions are often present in the lumina of the dilated acini. NCIT:C54183 MONDO:0006166 CCH UMLS:C1707446 EFO:1000199 columnar cell hyperplasia of breast