Anal dysplasia is changes in your body that could become anal cancer. Anal dysplasia isn’t cancer. Medical researchers believe variants of the human papillomavirus (HPV) cause nearly all cases of anal dysplasia. People can reduce their risk of developing anal dysplasia by being vaccinated against HPV and by reducing their risk of HPV infection.
Anal dysplasia is a term healthcare providers use to describe changes in your body that could become cancer in your anus. Anal dysplasia isn’t cancer. It’s a sign you could develop anal cancer. In anal dysplasia, cells in your anus — the last section of your intestine — become abnormal. Over time, these abnormal cells could start multiplying, creating tumors. These tumors can spread to other areas of your body.
Medical researchers believe variants of the human papillomavirus (HPV) cause nearly all cases of anal dysplasia. People can reduce their risk of developing anal dysplasia by being vaccinated against HPV and by reducing their risk of HPV infection. Researchers have identified several other factors that increase the risk that someone will develop anal dysplasia, including having human immunodeficiency virus (HIV).
Anal dysplasia starts in your mucosa, the moist inner lining of your anal canal. (Your anal canal extends from your anus to your rectum.) In anal dysplasia, healthy cells in your mucosa change into abnormal cells. These abnormal cells typically develop where your anal canal meets your rectum, but they can develop in the skin just outside your anus (perianal skin.)
Anal dysplasia doesn’t always cause symptoms. When it does, the symptoms may include things like having a very itchy anus or possibly feeling a lump or bump if you poke your finger into your anus. Some people with anal dysplasia notice warts in their anus. These warts aren’t cancer. They’re an HPV symptom.
Healthcare providers may refer to anal dysplasia as anal intraepithelial neoplasia (AIN) or as squamous intraepithelial lesions (SILs). Providers place AIN/SILs in two categories. They do that by examining cells under a microscope. AIN/SILs categories are:
Low-grade anal dysplasia (LSIL) doesn’t turn into anal cancer. A 2020 study estimated 3% to 14% of people with high-grade anal dysplasia (HSIL) develop anal cancer. The chance that anal dysplasia will become anal cancer varies based on people’s situations. For example, one study indicated about half of people with HIV and anal dysplasia developed anal cancer.
No, it’s not common. A 2018 review stated about 2 people in 100,000 have anal dysplasia.
Anal dysplasia affects people between ages 50 and 80. Nearly all people with anal dysplasia also have specific types of HPV.
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Anal dysplasia often causes no symptoms. When symptoms are present, they may include:
Medical researchers have identified several risk factors that increase the chance you’ll develop anal dysplasia. Risk factors include:
Healthcare providers may use several tests to diagnose anal dysplasia. If you’re being evaluated for anal dysplasia, a provider may ask about your medical history, including if you have HIV or HPV. Possible tests include:
Treatment varies based on the extent and kind of anal dysplasia you have. For example, if tests show you have low-grade dysplasia, your provider may simply monitor your situation to see if the dysplasia gets worse. (Remember, dysplasia sometimes appears and goes away without treatment.) If you have high-grade dysplasia, they may use one or more of the following treatments:
Each treatment has different side effects, from mild pain to mild bleeding. Your provider will select the treatment most likely to resolve your issue with the fewest side effects. They’ll explain the treatment options and what you can expect following treatment.
The most effective way to avoid anal dysplasia is to protect yourself against the HPV types that cause the condition. Ways to reduce your HPV risk include:
That depends on your situation. People who have an increased risk for anal dysplasia may benefit from regular screening. People at increased risk include:
It’s important to remember anal dysplasia isn’t anal cancer. It’s also important to remember having anal dysplasia doesn’t mean you’ll develop cancer. If you have anal dysplasia, a healthcare provider will evaluate your situation, recommend treatment and explain what you can expect.
Having certain variants of HPV increases the chance you’ll develop anal dysplasia. If you have HPV, take steps to protect yourself and your sex partners:
If you don’t have HPV, take steps to avoid HPV infections by getting the HPV vaccine.
You should talk to a healthcare provider if you:
If you’ve been diagnosed with anal dysplasia, you may want to ask the following questions:
A note from Cleveland Clinic
Anal dysplasia happens when you have changes in your anus that could become anal cancer. It’s important to remember anal dysplasia isn’t cancer and many times doesn’t become anal cancer. Anal dysplasia has some symptoms that may be embarrassing, like a persistent anal itch. And it’s commonly caused by human papillomavirus, a sexually transmitted disease that affects 1 in 4 adults in the U.S. But don’t let a potentially embarrassing symptom or cause keep you from talking to a healthcare provider.
Last reviewed by a Cleveland Clinic medical professional on 01/10/2023.
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