Histological classification of breast tumors in the General Rules for Clinical and Pathological Recording of Breast Cancer (18th edition)

The histological classification of breast tumors by the General Rule Committee of the Japanese Breast Cancer Society has been revised in the General Rules for Clinical and Pathological Recording of Breast Cancer (18th edition). In this article, the contents of the General Rules 18th edition are presented, and its revised points are briefly described in comparison with the classification of the General Rules 17th edition. The present classification takes into consideration the classification of breast tumors by the World Health Organization 4th edition, however, some differences remain. These differences will be briefly mentioned.