Ductal carcinoma in situ

In oncology, ductal carcinoma in situ (DCIS), also called noninfiltrating intraductal carcinoma, is "a noninvasive (noninfiltrating) carcinoma of the breast characterized by a proliferation of malignant epithelial cells confined to the mammary ducts or lobules, without light-microscopy evidence of invasion through the basement membrane into the surrounding stroma."

The importance of DCIS is not clear.. However, it may benefit from treatment.