Infiltrating lobular carcinoma without lobular carcinoma in situ

Abstract

Seventeen patients had breast carcinoma with cell populations and histologic growth patterns identical to the infiltrating lobular carcinomas associated with lobular carcinoma in situ (CIS). However, no lobular CIS was demonstrable in the breasts. Nonetheless, seven of the 17 patients have had carcinoma identified in the second breast either synchronously or metachronously. These contralateral carcinomas include infiltrating lobular carcinoma with lobular CIS (two cases), lobular CIS alone (one case), comedocarcinoma and infiltrating ductal carcinoma (one case each). The frequency of lobular CIS in the contralateral breast is similar to that reported when the ipsilateral breast contains lobular CIS alone. This is interpreted as indirect evidence that lobular CIS was probably present in the breast with infiltrating cancer but was destroyed by the neoplasm or missed due to sampling deficiencies. We conclude that the diagnosis of infiltrating lobular carcinoma can be made in the absence of lobular CIS. The clinical importance of recognizing this specific carcinoma lies in the high risk for invasive cancer in the second breast as well as the occurrence of lobular carcinoma in situ. Copyright © 1972 American Cancer Society