Updated WHO classification of tumors of the breast

Abstract

In the fifth edition of the World Health Organization (WHO) classification of tumors of the breast, the histological features of the lesions continue to form the basis of the classification; however, molecular pathology nowadays provides approaches for improved diagnostics and prediction of prognosis and treatment response, which have been incorporated into the update of the classification. The most important changes are presented, which include changes in the histological classification of invasive carcinomas, the subtyping of lobular carcinoma in situ (LCIS) and the dignity criteria of phyllodes tumors.