[Definition and significance of carcinoma in situ of the breast gland].

1. Preinvasive phases of the cancer of the breast are observed with the intraductal cancers of the bigger ducts and with the so-called lobular carcinoma in situ. It shows, however, that the carcinoma of the ducts, above all the comedo-carcinoma, have to be considered as invasive cancers in more than 75%. These forms extend to the lobuli of the breast. 2. The Morbus Paget bases in one third on an intraductal preinvasive carcinoma, in two thirds on an invasive cancer. 3. This chapter deals with the differential diagnosis of the papilloma and papillary carcinoma. 4. Intralobular proliferations of the epithelium are observed at the periphery of undifferentiated cancers as secondary intraductal carcinoma and as primary lobular carcinoma. The so-called intralobular carcinoma in situ is in 15,2% followed by an invasive carcinoma after an interval of up to 28 years, and in 23% ipsilateral, in 9,5% contralateral. As therapy the subcutaneous or simple mastectomy is proposed.