Anal dysplasia is the presence of abnormal pre-cancerous cells in the anal canal which may eventually progress to the development of anal cancer. The anal canal (the last few inches of the intestine) and the perianal area (the skin surrounding the anus) are susceptible to multiple health problems including hemorrhoids, anal fissures, anal warts and anal dysplasia (which can transform into anal cancer).
The most common cause of anal warts, anal dysplasia and anal cancer is infection with the human papilloma virus (HPV). HPV can infect the anus and perianal area, the mouth and upper airway, the cervix in women, and even the skin (causing warts). HPV infection at each different site can be acquired through sex or through skin contact and is very common in the United States – the CDC estimates that 85% of people will get an HPV infection in their lifetime. Some types of HPV are likely to cause warts to develop, some types are likely to cause dysplasia to develop, and some are unlikely to cause any disease process at all. People with weakened immune systems, including those receiving immune-suppressing medications and those with HIV infection, are more likely to acquire HPV infection and to develop disease related to HPV infection.
People with an elevated risk of developing HPV-related disease require monitoring and testing for anal dysplasia, in order to prevent or identify the development of anal cancer. Monitoring and testing can take several forms, but the most comprehensive evaluation is by high-resolution anoscopy (HRA). HRA is a brief procedure which is performed in the clinic setting rather than the operating room, and involves the use of a small device called the anoscope to make the anal canal visible and the use of a special microscope called a colposcope to magnify the tissue to identify any areas of abnormalities. Areas with abnormal characteristics may require a biopsy for further examination, and if high-grade dysplasia is identified on biopsy then the area can be treated.
Factors that contribute to an increased risk of the development of anal dysplasia include:
Anal dysplasia often has no associated symptoms. Symptoms in the anorectal area that would increase concern and prompt evaluation include anal pain or discomfort, bleeding, and itching. However, these symptoms can be present due to hemorrhoids or other conditions that are not precancerous.
Similar to screening for cervical dysplasia with a cervical Pap smear, screening for anal dysplasia can be performed with an anal Pap smear. An anal Pap smear is performed by collecting cells from a swab that was inserted into the anus—those cells are examined under a microscope to identify pre-cancerous cells or dysplasia. If there are abnormalities on the anal Pap smear then providers may refer to the anal dysplasia clinic for a more advanced evaluation with high-resolution anoscopy (HRA). In certain cases people with increased risk for HPV-related disease in the anorectal area or at increased risk for anal cancer may also be referred to the anal dysplasia clinic without an anal Pap smear.
Anal dysplasia can be diagnosed by the presence of abnormal cells on an anal Pap smear, or specific areas of anal dysplasia can be diagnosed by biopsy of areas identified as possibly abnormal during HRA. A biopsy is performed by collecting a tiny piece of tissue for examination in the lab. Cells from an anal Pap smear or tissue from a biopsy can be graded on the level of abnormality: normal, metaplasia (overgrown, but normal), atypical with uncertain significance (not clearly dysplasia but some slight abnormalities), low-grade lesions and high-grade lesions (nearest to the eventual development of anal cancer).
Low-grade lesions are low risk and generally do not require treatment, they can be monitored for signs of progression. If any areas of high-grade dysplasia are found on biopsy then these can be treated either by electrocautery treatment or in some cases with a topical cream medication that can be used at home. Electrocautery treatment is the destruction of the lesion with heat – this can cause some mild pain and slight bleeding afterwards, but can be done in a clinic or office setting and often removes a lesion in one treatment. Topical cream medication can be helpful for some lesions but not be appropriate for all lesions and may take weeks or months to be effective.
The best known methods to prevent anal dysplasia are:
An appointment at the anal dysplasia clinic will likely include an exam and high-resolution anoscopy (HRA) procedure. There is no specific preparation required for this exam – it is not necessary to perform any special cleansing procedures or to use an enema prior to this procedure, and these preparations may actually cause irritation to the anorectal area. During the clinic visit the physician will discuss your health and the procedure with you first, and then begin preparation and the procedure. We understand that this procedure may seem intimidating and uncomfortable to many patients, but our team works to create a safe and respectful environment for our patients. The examination procedure will likely include appropriate draping and positioning, a visual exam, a digital rectal exam (an exam with your provider’s gloved and lubricated finger into the anus and lower part of the rectum to feel for lumps or other abnormalities), an anal Pap test when appropriate (insertion of a moist swab like a Q-tip into the anal canal), and insertion of a lubricated plastic instrument (anoscope) into the anal canal to examine the area through a microscope.
If any areas of concern are identified then your provider will perform a biopsy to take a tiny piece of tissue from the anorectal area for examination in the lab. After a biopsy it is common to have slight bleeding with bowel movements, and the area may be tender for a few days.
The team at the anal dysplasia clinic at Brigham and Women’s includes colon and rectal surgeons, with additional expertise on surgical management of anorectal diseases and anal cancer, as well as an infectious disease specialist, with additional expertise on management and prevention of HPV infection as well as HIV infection and other anorectal sexually transmitted infections (STIs). All physicians perform comprehensive patient evaluations, including HRA, and may collaborate to develop appropriate treatment and monitoring plans. Meet our physician team below. We also collaborate with physicians in other specialties, such as Dermatology and Gynecology, when appropriate.
The anal dysplasia clinic at Brigham and Women’s Hospital is located within the colon and rectal surgery clinic in the Brigham Surgical Specialties. Call 617-732-6653 or contact one of our specialists in the care team above in order to schedule an appointment.
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