We call intraductal lesions of the breast, for example, intraductal papilloma, duct papillomatosis and noninvasive ductal carcinoma, "papillary lesions". Borderline lesions, if such exist in the breast, are included among papillary lesions. So accuracy of histopathological diagnosis is very important for research of precancerous lesion. To clarify the present conditions and problems of histopathological diagnosis of papillary lesion of the breast, fifty consecutive papillary lesions out of consultation cases were diagnosed using three categories, benign, borderline and malignant, by five pathologists. The rate of agreement of all diagnoses by five pathologists was only 20%. The borderline incidence was widely distributed from 0% to 46%. These results revealed that histopathological differential diagnosis between benign and malignant of papillary lesion was very difficult. This difficulty seems to be caused by various histological features and different criteria of histological atypia from other organs of papillary lesion of the breast.