ductal carcinoma in situ (DUK-tul KAR-sih-NOH-muh in SY-too)
A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, ductal carcinoma in situ may become invasive cancer and spread to other tissues. At this time, there is no way to know which lesions could become invasive. Also called DCIS and intraductal carcinoma.