Information on Anal Dysplasia and Anal Pap Smear

What is Anal Dysplasia?

Anal Dysplasia is a pre-cancerous condition associated with past or present exposure to Human Papillomavirus (HPV). It refers to abnormal changes in the cells that make up the lining (mucosa) of the anal canal. Abnormal cells clustered together form a visible pattern called a lesion. Low-grade lesions (LSIL) may progress to high-grade lesions (HSIL), which are more serious because they have the potential to progress to cancer in some people. Not all lesions progress to cancer and most of them won’t. Some may regress, meaning they shrink or even disappear. Some may persist, meaning they remain present without changing. The anus extends from the anal opening to about 1.5 inches inside the body to join the rectum. The portion inside the body is called the anal canal. Anal dysplasia occurs mainly in two places: at the "junction," where the anal canal meets the rectum or put another way, where the outside skin meets the inside rectal skin; and in the peri-anal skin, which is the skin just around the anal opening.

Goals of Treatment

Anal pap tests, High Resolution Anoscopy (HRA) and proper treatment can prevent abnormal cells that are not yet cancerous (called dysplasia) from becoming tumors that will require chemotherapy, radiation treatment, and/or surgery. Pap smears of the cervix and colposcopy are highly successful in preventing cervical cancer in women, and it is likely that the same success can be achieved with anal cancer in men and women. The goal is to destroy the abnormal cells before they become cancer.

Who is at risk for Anal Cancer?

  1. HIV infection
  2. Men who have sex with men (MSM)
  3. Having many sex partners or a partner with many sex partners
  4. Having receptive anal sex
  5. History of anal or genital warts
  6. History of anal fissures, fistulas, and hemorrhoids
  7. Women with a history of cervical, vaginal, or vulvar dysplasia or cancer
  8. Smoking cigarettes
  9. Organ transplant recipients and other groups with reduced immunity

What is an Anal Pap Test?

An anal Pap test is performed by inserting a swab into the anus while you are lying on your left side on the exam table in a fetal position or standing bent over the exam table. The swab is rotated around the entire anal canal to collect some superficial cells. Those cells are then examined in a lab under a microscope.

Anal Pap Results

Benign or normal: There are no abnormal changes in the cells and no further evaluation or treatment is needed.

Unsatisfactory or Inadequate: The specimen collected was not adequate and your provider will likely recommend a repeat anal pap test at your next appointment.

Atypical Squamous Cells of Undetermined Significance (ASCUS): The cells are abnormal, but no definite diagnosis can be made. These are non-cancerous changes. It may be caused by inflammation or associated with dysplasia.

Low-grade Squamous Intraepithelial Lesion (LSIL): Mild dysplasia. LSIL could mean that you have anal warts or there could be precancerous areas.

High-grade Squamous Intraepithelial Lesion (HSIL): Moderated to severe dysplasia. The cells in your anus show changes most likely caused by HPV. This is a sign you have precancerous areas in your anus. This does not mean you have cancer.

Squamous Carcinoma: Cells show severe changes that are very suspicious for cancer.

If the Anal pap test has any abnormal result, the next step is to get a magnified exam of the anal canal. The procedure is called High Resolution Anoscopy (HRA).

More information about anal dysplasia and anal cancer: