atypical lobular breast hyperplasia (Monarch Disease Ontology id MONDO_0006098) is lobular neoplasia characterized by lobular epithelial proliferation that does not completely fill the lobular unit of the breast. Also known as: ALH, atypical breast lobular hyperplasia, atypical lobular hyperplasia, atypical lobular hyperplasia of breast, atypical lobular hyperplasia of the breast.