‘CIN’ is Cervical Intraepithelial Neoplasia, also known as Dysplasia.

What Is CIN?

CIN is an abnormality in the skin covering the cervix. The cells are growing faster than they should, and without treatment, occasionally will develop into a cancer over many months or years.

CIN is short for Cervical Intraepithelial Neoplasia and means the same as dysplasia. CIN 1 or mild dysplasia usually correlates with a smear showing mild dyskaryosis, CIN 2 or moderate dysplasia with moderate dyskaryosis and CIN 3 or severe dysplasia with severe dyskaryosis.

Below we’ve included some information and commonly asked questions about CIN.


What does CIN mean?

CIN is short for cervical intraepithelial neoplasia. This seems a complicated medical term, but when translated it is easy to understand. “Cervical” is because the skin is covering the cervix. “Intra” means within and “epithelial” means skin, so intraepithelial means that the abnormal cells are confined to the skin and therefore have not spread at all. “Neoplasia” is a collective term for any areas of tissue where the cells are growing faster than they should. “Neo” means new and “plasia” means growth. Another term that is used instead of CIN is “dysplasia”, where “dys” means abnormal.

How is CIN or dysplasia graded?

The skin of the cervix is many cells thick and is relatively tough. The cells in the bottom layer are called basal cells and are tall columnar cells, which are actively dividing. The cells tend to move up through the layers as more cells are produced and initially become rounded and then flatten as they reach the surface of the skin. Finally they fall off or are exfoliated.

Abnormalities of the cells originate in the lower part of the skin. If they involve only the lower third it is called CIN 1 or mild dysplasia, if it involves the lower and middle third CIN 2 or moderate dysplasia and CIN 3 or severe dysplasia is when the full thickness of the epithelium is involved.

Where is CIN identified on the cervix?

CIN usually develops at the junction between the squamous skin of the outer part of the cervix or ectocervix, and the thin columnar epithelium that lines the canal of the cervix or endocervix which connects to the inside of the uterus. This junction is called the squamo-columnar junction, and is usually seen on the ectocervix near the canal. However, it can be further away from the canal on the ectocervix, or hidden within the canal of the cervix.

What is an erosion?

The term erosion refers to a normal appearance of the cervix. The skin covering the outer part of the cervix or ectocervix is many cells thick and is similar to the tough external skin covering our body. This skin appears pink. The skin from the canal of the cervix is delicate skin one cell thick and is more similar to the skin lining internal organs. Because the skin is so thin, it appears red. This delicate skin is often seen on the central part of the ectocervix surrounding the canal, and because it is red, was called an erosion in error. A more accurate term for it is an ectropion.

What is carcinoma-in-situ?

This term is not in current use but was previously used for some CIN 3 lesions. The term “carcinoma” may sound a little frightening, since it is another word for cancer. However the “in-situ” part of this term reflects that the abnormality is confined to the skin, and so is not behaving like a cancer.