Abnormal Anal Pap Smear, Anal Dysplasia and Anal Cancer

HPV Infection, Abnormal Anal Pap Smear, Anal Dysplasia and Anal Cancer

Abnormal anal pap smears, anal dysplasia and anal cancer are all caused by human papilloma virus (HPV).

What Is Human Papilloma Virus (HPV)?

HPV is a common virus which can be transmitted sexually. There are over 100 types of HPV. Most everyone is exposed to the virus at one point in their lives; most people “clear” the virus, but some people may harbor the virus chronically. HPV infection may present differently: some HPV types cause warts while other HPV types cause anal and cervical cancer.

Risk Factors for HPV: Men and women are equally susceptible to HPV infection.

  • Women: History of cervical high grade dysplasia or cervical cancer
  • Women and Men: HIV infection
  • Women and Men: History of receptive anal sex. Anal HPV can occur even in the absence of anal intercourse
  • Women and Men: Other HPV related diseases such as warts or changes in the skin of the genital area
  • Women and Men: Immunosuppression from diseases or from medications which suppress the body’s immune response (for example, anti-rejection medications for transplant patients)

HPV Prevention: There is no prevention strategy which is 100% effective in preventing HPV warts and HPV-related cancers.

  • HPV Vaccines: They are highly effective in preventing both HPV warts and HPV-related cancers when given before becoming sexually active
  • Practicing safe sex reduces the risk of getting HPV; condoms are partially protective
  • Stopping cigarette smoking decreases HPV disease and risk of recurrence
  • Treating HIV with antiretroviral therapy may reduce the risk of getting anal dysplasia

What Is Anal Dysplasia?

Anal dysplasia is a pre-cancerous condition which occurs when the cells of the lining of the anal canal undergo abnormal changes. The anal canal is the last few inches of the intestine. Anal dysplasia may progress from low-grade (low risk) changes to high-grade (high risk) changes before it turns into cancer.

What Causes Anal Cancer?

90% of anal cancers are caused by the human papillomavirus (HPV). The oncogenic (cancer-causing) HPV types are responsible for transformation of the anal canal cells from normal to pre-cancerous to cancerous. Anal cancer may develop slowly over a period of years. Anal cancer may occur inside the anal canal where the anus meets the rectum: it is usually not visible in that position. Or it may develop in the skin just outside of the anal canal opening. In such cases, the person may be aware of a visible or palpable, often painful growth.

What Are the Symptoms of Anal Cancer?

Sometimes there are no specific symptoms of anal cancer until it is quite advanced. As mentioned above, there may or may not be a visible or palpable growth. People may also have anal pain, bleeding and discomfort.

These same symptoms can be caused by other benign conditions, like hemorrhoids or anal fissures. This is one of the reasons you should be seen and examined when you have those symptoms, so the correct diagnosis is made. At a minimum, you should have the following examinations:

  • Digital Rectal Exam: your provider places a gloved finger in the anal canal to feel for lumps
  • Routine Anoscopy: a visual examination of the anal canal. A short instrument is placed in the anal opening to allow the provider to see the lining of the anal canal.

Diagnosis of Anal Dysplasia

The diagnosis of anal dysplasia may be made by performing an anal pap smear. Just like a cervical Pap smear, cells are collected from a swab inserted into the anus. Those cells are then examined by a pathologist looking for pre-cancerous or dysplastic changes. Male/female patients with any of the following risk factors should have an anal pap smear:

  • History of receptive anal sex
  • HIV infection (HIV positive status, even when viral load is undetectable and CD4 count is normal)
  • History of cervical high grade dysplasia or cervical cancer
  • Other HPV related disease: genital warts or changes in the skin of the genital area
  • Immunosuppression from disease or medications suppressing the immune system

Follow-Up of Anal Dysplasia Is Based on the Results of Anal Pap Smear

Results of anal Pap smear may be normal or abnormal. Abnormal results may be described in a number of different ways: ASCUS (atypical squamous cells of undetermined significance; ASCUSH (atypical squamous cells of undetermined significance high grade); LSIL (low grade squamous intraepithelial lesion); HSIL (high grade squamous intraepithelial lesion); or AIN (anal intra-epithelial neoplasia) of various grades. Any description of abnormal anal pap smear usually triggers a recommendation to perform high resolution anoscopy.


Results of Anal Pap Smear

Normal Anal Pap Smear

Abnormal Anal Pap Smear

HIV Positive

Repeat anal pap smear in 1 year

Refer for high resolution anoscopy (HRA)

HIV Negative

Repeat anal pap smear in 2 years

Refer for high resolution anoscopy (HRA)


High Resolution Anoscopy (HRA) uses magnification to obtain a more detailed view of the anal canal. The provider inspects carefully the entire anorectal junction under high magnification. HRA offers the opportunity to both diagnose and treat anal dysplasia. Suspicious or atypical areas can be biopsied, and the lesions may be destroyed in the course the same procedure.

HRA is available in specialized centers like the Pelvic Floor Center. It is important to understand that sigmoidoscopy and colonoscopy are not reliable for adequately examining the anal area.

The results of biopsies taken during the HRA are usually available within a few days (3-5 days). Recommendations for the next step are based on the results


HRA Biopsy Results

What Does That Mean?

Risk of Developing Anal Cancer




No evidence of abnormal changes in the sample


No treatment needed

Surveillance as recommended by provider

Low-Grade Dysplasia (AIN-1, LGAIN, LSIL)

Mild or low-grade dysplasia

Anal warts


No treatment needed

Visible warts are usually treated

May be watched for possible signs of progression. Surveillance as recommended by provider

High-Grade Dysplasia (AIN-2, AIN-3, HGAIN, HSIL)

Severe or high-grade dysplasia (pre-cancerous changes)


Should be treated

Surveillance as recommended by provider


Visible warts are usually treated even if they are not pre-cancerous lesions. High-grade lesions should be treated. There are multiple treatment options. Some include:

  • Lesion destruction with electrocautery (heat) or by infra-red coagulation (IRC- intense beam of light). It may be uncomfortable and may cause some mild pain and slight bleeding. This may be done at the Pelvic Floor Center under local anesthesia; or in the operating room under anesthesia for more advanced cases. One treatment may be enough, but the need for repeated treatment is not uncommon.
  • Trichloroacetic acid (TCA): the lesion is treated by being touched with acid-soaked cotton. Four or more treatments may be needed over several weeks. There is minimal, if any discomfort. There is no need for anesthesia. This is may be done at the Pelvic Floor Center.

After Treatment: Surveillance

Anal dysplasia can be treated successfully with very close follow up and monitoring. Individuals with low-grade lesions will generally have a repeat HRA in 1 year. Individuals with high-grade lesions will have a repeat HRA every 3-6 months. This will continue until there is no further evidence of high-grade dysplasia.

Late Policy

New patients must complete the necessary paperwork prior to their first visit using the online patient portal. If the paperwork delays your appointment start time, your appointment might be canceled at the discretion of the provider.

If a patient arrives past their scheduled time and/or do not have their paperwork completed, their appointment might be canceled at the discretion of the provider.  This is to ensure that the patients who arrive on time do not experience delayed waits to see their provider. If you arrive late, you may be asked to reschedule. If you choose to wait, we will try to minimize your wait time as best as possible, however we need to provide timely care to our other patients as well.