adenocarcinoma in situ

Definition of adenocarcinoma in situ
National Cancer Institute

adenocarcinoma in situ

(A-deh-noh-KAR-sih-NOH-muh in SY-too)
A condition in which abnormal cells are found in the glandular tissue, which lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices, and other fluids. These abnormal cells may become cancer and spread into nearby normal tissue. Adenocarcinoma in situ occurs most often in the cervix and lung. Also called AIS.

Source: NCI Dictionary of Cancer Terms