[Circumstances in the detection of carcinoma in situ of the breast. Apropos of 12 cases].

In France, 7,000 women die yearly of cancer of the breast, and 25,000 new cases are registered. The seriousness of the illness and its frequency show how important it is to diagnose it early at a stage before invasion or in situ (where 95 to 100% can be cured). In 4 years, at the University Hospital of Rennes, 90 out of 446 patients who were operated on for breast lesions had invasive cancer of the breast, i.e. 20%. 12 had a carcinoma in situ of the breast (C.I.S.E.), constituting 2.6%, of which 9 were in situ duct carcinomas and 3 in situ lobular carcinomas. In situ carcinoma of the breast can take almost any clinical form (a nodule, pain in the breast, mastitis, blood stained discharge from the nipple or Paget's disease). This means that lobular carcinoma in situ is always a surprise when diagnosed histologically in a lesion that is clinically benign. Since the anatomo-pathological diagnosis is difficult, a simple examination of the breast is not to be relied on in cases of carcinoma in situ of the breast. Mammography is the only truly valuable investigation in early diagnosis of C.I.S.E.