Pathology dictionary -
CIS stands for carcinoma in situ. Carcinoma in situ is a diagnosis that describes an early non-invasive type of cancer. There are many different types of carcinoma in situ and the type depends on where in the body the disease starts.
When examined under the microscope, the cancer cells in carcinoma in situ look abnormal but they have not spread into the surrounding normal tissue.
Can carcinoma in situ spread to other parts of the body?
No. The cancer cells in carcinoma in situ do not have the ability to spread to lymph nodes or distant parts of the body. The movement of cancer cells to another part of the body is called metastasis.
Why is this important? Without treatment, the cancer cells in carcinoma in situ will eventually spread into the surrounding normal tissue. The movement of cancer cells into the surrounding tissue is called invasion.
Types of carcinoma in situ
In many parts of the body, carcinoma is given a special name that describes the type of cells found in that part of the body.
Some common types of carcinoma in situ include:
Breast - Ductal carcinoma in situ (DCIS).
Cervix - High grade squamous intraepithelial lesion (HSIL).
Bladder - Urothelial carcinoma in situ.
Lung - Adenocarcinoma in situ (AIS).
Mouth - Squamous carcinoma in situ.