A critical appraisal of existing classification systems of epithelial hyperplasia and in situ neoplasia of the breast with proposals for future methods of categorization: where are we going?

Current classification systems for borderline lesions of the breast including epithelial hyperplasia, atypical hyperplasia, and ductal carcinoma in situ fall short of the ideal. They present pathologists with problems of recognition or clear distinction and clinicians with difficult management choices. In addition, recent evidence indicates that different pathogenetic lesions are present in some categories. This article presents a brief critical appraisal of the existing classifications and offers suggestions for revision using a model of pathogenetic lineage.