This is precancer and is often seen adjacent to infiltrating cancer. It is only significant when there is a lot of it. Even then it does not indicate that the cancer is aggressive but rather that it may be harder to remove in its entirety. back to pathology report

in situ cancer that has not spread outside of the breast duct

Breast cancer that originates in the ducts. Understanding Breast Cancer

in situ — Stage 0 breast cancer. Cancer cells are present in the lining of lobules or ducts, but have not spread to the surrounding fatty tissue or nearby lymph nodes.

Cancer located in one of the ducts of the breast.

The most common form of breast cancer, which begins in the lining of the tubes that carry milk to the nipple.

A cancer developing in the epithelium (lining) of ducts.

The most common type of breast cancer. It begins in the cells that line the milk ducts in the breast.

cancer that is found in the ducts and tissue of the breast.

Ductal carcinoma is a very common type of breast cancer in women. It comes in two forms: infiltrating ductal carcinoma (IDC), an invasive cell type; and ductal carcinoma in situ (DCIS), a noninvasive cancer.