What is anal dysplasia? Causes, treatment and outlook
January 30, 2025
Medically Reviewed | Last reviewed by Craig Messick, M.D., on January 30, 2025
Anal dysplasia is a condition in which cells in the anal canal change and become abnormal. Anal dysplasia is not cancer. But it can turn into anal cancer over time.
We spoke with colon and rectal surgeon Craig Messick, M.D., to learn more about anal dysplasia, including what causes it and how it’s treated.
What causes anal dysplasia?
The human papillomavirus (HPV) is the cause of all anal squamous cell dysplasia.
Anogenital dysplasia refers to abnormal cell changes in the anus or genitals. These are just a few locations in the body where HPV is commonly found. Other common locations include the oropharynx, back of the tongue, tonsils, vulva vagina, cervix and penis because these are areas of the body where the tissues replicate the fastest.
The HPV vaccine can prevent the most concerning and common types of HPV. This will also prevent you from developing anal dysplasia, or even common benign “warts.”
The HPV vaccine is encouraged for boys and girls ages 9-26. Due to the immune system's development, it is most effective when given at ages 11 to 12. The series should be completed by age 14 when only two shots are needed. After age 15, three shots are required.
Adults ages 27 to 45 who are not vaccinated should talk to their doctor to see if the vaccine would benefit them.
What are the symptoms of anal dysplasia?
Anal dysplasia often doesn’t have any symptoms. If you do develop symptoms, they may include:
- itching
- pain or irritation
- bleeding
The symptoms are not from the dysplasia itself; rather they come from the use of your bottom. For example, wiping yourself after using the restroom may irritate the area because you’re disrupting the cells on the surface of the anus. Itching is an inflammatory response to that. But if it doesn’t seem normal, then it isn’t and you should seek a physician’s opinion and get an exam.
How is anal dysplasia diagnosed?
There are several tests that can help diagnose anal dysplasia. If you visit your doctor with symptoms, they’ll ask about your medical history to better understand your risk. You may receive any of the following tests:
Digital rectal exam
Your doctor will use a gloved finger to feel inside your anus to check for any lumps or other abnormalities. This should never hurt but reproduce the feeling of having a bowel movement.
Collection of anal cytology
A swab similar to a Q-tip is used to collect cells from the anus, which are examined under a microscope along with DNA testing to see which type(s) of HPV you might have. This is very important for any anal lesion we suspect to be HPV-related. There are so many different types of HPV, so it’s important we understand which ones are potentially causing the lesions.
High-resolution anoscopy
A very dilute vinegar solution and a small microscope are used to examine the anal canal’s lining.
Biopsy
Your doctor will take a tissue sample from the anus and send it to a lab to be examined by a pathologist.
Anal dysplasia may be diagnosed as low-grade or high-grade. This refers to how abnormal the cells and tissue look under a microscope.
- Low-grade dysplasia does not progress to cancer. It usually goes away on its own.
- High-grade dysplasia can turn into cancer but not every time. Still, that’s why it’s best to treat it.
What are the treatment options for anal dysplasia?
To treat anal dysplasia, we target the lesions causing the symptoms. Treatment may include:
- Topical creams: You apply cream to the area where the lesions are. Your doctor will monitor you for three months to see if the lesions go away or shrink. If this does not clear the lesions, your doctor may consider other treatments.
- Electrocautery ablation: This treatment uses heat to burn and destroy the lesion. This can often be done during a high-resolution anoscopy.
We do not recommend surgery to treat anal dysplasia. Surgery can disfigure the anal anatomy, possibly leading to dysfunction. Plus, it will not cure HPV, which is what causes anal dysplasia, and the dysplasia is very likely to return.
Does anal dysplasia always lead to cancer?
No. If you have anal dysplasia, it does not mean you will get anal cancer.
Remember, low-grade dysplasia is not a precursor to cancer.
But high-grade anal dysplasia can lead to anal cancer. This has mostly been studied in high-risk groups, such as those with weakened immune systems due to the human immunodeficiency virus (HIV) or other conditions.
Results from a Phase III clinical trial showed that patients living with HIV who received treatment for high-grade anal dysplasia were 57% less likely to develop anal cancer compared to patients living with HIV who did not receive treatment for anal dysplasia.
How can anal dysplasia be prevented?
Avoiding HPV exposure may not be possible, but getting the HPV vaccine is the best way to avoid getting HPV, thereby preventing anal dysplasia.
HPV 16 is a strain that is commonly linked to anal cancer in men and women. That’s why we treat high-grade lesions, especially those related to HPV 16. This can prevent the lesions from ever turning into anal cancer.
There’s a lot of research happening in this space. We want people to have productive, non-embarrassing talks with their doctors about anal health, especially those who are experts in anal HPV-related diseases. That way, we can prevent more cases of anal cancer.
Request an appointment at MD Anderson online or call 1-877-632-6789.
If you have anal dysplasia, it does not mean you will get anal cancer.
Craig Messick, M.D.
Physician