Lobular carcinoma in situ (LCIS) is a type of abnormal cell change found in the milk glands (lobules) of the breast. LCIS is not cancer and the abnormal cells don't spread beyond the lobules. But having LCIS makes you more likely to develop breast cancer later in life.

LCIS usually doesn't cause any symptoms or show up on a mammogram. In most cases, it's found during a breast biopsy done for another problem.