Squamous intraepithelial lesion (SIL)

The definitive way to diagnose a squamous intraepithelial lesion is with a biopsy done during a

colposcopy. A biopsy is the process of removing living tissue or cells from organs or other body parts of

patients for examination under a microscope or in a culture to help make a diagnosis, follow the course of

a disease, or estimate a prognosis. A culture is an artificial way to grow cells or tissues in the laboratory.

The above procedures are usually performed by an OB/GYN, which stands for obstetrician and

gynecologist. An obstetrician is a physician (medical doctor) who specializes in obstetrics, which is the

science that deals with the care of women and their fetuses during pregnancy and childbirth, and during

the events that come before and soon after birth. A gynceologist is a physician who specializes in

gynecology, which is the science that deals with the health care of women, including diseases and

normal physical care of the female reproductive system.

DOES HAVING A SQUAMOUS INTRAEPITHELIAL LESION MEAN THAT CANCER IS PRESENT?

Having a squamous intraepithelial lesion does not mean that cancer is present. Cancer is an abnormal

growth of new tissue characterized by uncontrolled growth of abnormally structured cells that have a

more primitive form. The presence of squamous intraepithelial lesions represents changes in cells that

can occur before cancer is present. Thus, squamous intraepithelial lesions are often seen by doctors as

warnings that cancer of the cervix may occur at a later date.

It should be noted that the chances of having a high grade intraepithelial lesion showing up on a Pap

smear with invasive cancer of the cervix already being present is less than 1%. Also, only about 1.5% of

women with a high grade intraepithelial lesion that shows up on a Pap smear will progress to cancer of

the cervix within the next 24 months.

HOW ARE SQUAMOUS INTRAEPITHELIAL LESIONS TREATED?

Since squamous intraepithelial lesions can progress to cancer of the cervix, it is important for them to be

treated. The results of the colposcopy, and not the Pap smear, will provide the basis for treatment. This

is because a colposcopy (combined with a biopsy) is a more definitive test than the Pap smear.

The goal of treatment is to destroy and/or remove the abnormal cells on the cervix so that new healthy

cells will grow over the area where the abnormalities were present. Squamous intraepithelial lesions can

be destroyed by applying below-freezing temperatures to them, by using lasers, or by applying heat

and/or electrical currents. If abnormal areas of tissue need to be totally removed, a colposcopy is often

used as a visual aid during surgery. Removal of the tissue can take place during the biopsy or at a later

time if the patient desires.

It is important to note that if there is disease inside the canal (passageway) of the cervix, doctors do not

freeze the disease tissue. Freezing is generally used in small areas of abnormality (even if they are

severe) that do not enter the canal of the cervix. Freezing tissue usually only takes a few minutes to do

in the doctor's office. Healing from this freezing procedure will take about 3 weeks. A watery liquid will

usually come out of the vagina during the healing process after the freezing procedure.

Destroying tissue with laser or heated electrical current is usually more appropriate for larger areas of

abnormality. Presently, this is the most frequently used treatment for high grade intraepithelial lesions.

Larger abnormal areas (even if they are mildly abnormal) are more than an inch wide, more than a half

inch from the bone by the cervix, or in more than two quadrants of the cervix. A quadrant is a division into

four areas. Abnormal areas that enter the canal of the cervix generally respond best to treatment with

laser therapy or electrical current.

The abnormal cells that are removed are usually located at the transformation zone of the cervix. The

transformation zone is located in the outside of the cervix or in the canal of the cervix. The

transformation zone is the area where tall cells shaped like a column (known as columnar cells) are

transformed (changed) into flat cells known as squamous cells. It is in the transformation zone that

abnormalities develop. In general, any procedure that destroys squamous intraepithelial lesions on the

cervix cures the condition in about 85% of the cases.

WHAT IS THE ORIGIN OF THE TERM, SQUAMOUS INTRAEPITHELIAL LESION?

Squamous intraepithelial lesion comes from the Latin word "squama" meaning "scale," the Latin word

"intra" meaning "within," the Greek word "epi" meaning "upon," the Greek word "thele" meaning "nipple,"

and the Latin word "laesus" meaning "an injury." Put the words together and you have "scale within upon

nipple an injury."