Atypical lobular and papillary lesions of the breast: a follow-up study of 30 cases.

Sections from 879 consecutive breast biopsies performed for clinically and grossly benign disease between 1962 and 1966 were reviewed. Twenty-four cases of undiagnosed lobular carcinoma in situ or atypical lobular hyperplasia and six cases of intraductal papillary carcinoma were found. Only one patient later developed invasive carcinoma, an infiltrating lobular carcinoma in the ipsilateral breast, which was diagnosed seven years after the biopsy containing lobular carcinoma in situ. Invasive cancers have not been found in other patients who have a median follow-up period of eight years.