carcinoma in situ

Pronunciation: (KAR-sih-NOH-muh in SY-too)

A group of abnormal cells that remain in the place where they first formed. They have not spread. These abnormal cells may become cancer and spread into nearby normal tissue. Also called stage 0 disease.

Source: NCI Dictionary of Cancer Terms

Caption: Carcinoma in situ (CIS) is a group of abnormal cells that are found only in the place where they first formed in the body (see left panel). These abnormal cells may become cancer and spread to nearby normal tissue (see right panel).

Date last modified: 2014-11-19