This study is designed to establish the prevalence of anal squamous intraepithelial lesion (ASIL) in patients with inflammatory bowel disease (IBD) and healthy controls.

IBD patients attending the Stanford Inflammatory Bowel Disease (IBD) clinic and age-matched healthy controls are screened for eligibility. Informed consent is obtained for eligible subjects. An anonymous self-administered questionnaire is administered to assess risk factors for HPV. For IBD patients, information regarding IBD diagnosis and treatment is obtained.

An anal pap smear is performed at the time of a clinic visit or at the time of an already scheduled colonoscopy. Samples are collected and processed at Stanford pathology where a blinded pathologist reads all specimens. Human Papillomavirus (HPV) DNA testing is performed on all specimens. All patients with anal squamous intraepithelial lesion (ASIL) are referred to a colorectal surgeon for further recommendations or treatment, which includes a high-resolution anoscopy.

Inclusion Criteria:

• All IBD patients followed in the IBD clinic and healthy controls who are greater than 18 years old

Exclusion Criteria:

• History of HPV vaccination
• Pregnancy
• Other immunosuppressed states (i.e. systemic lupus erythematosus, rheumatoid arthritis, cancer, Human Immunodeficiency Virus (HIV), transplant)
• IBD patients who don't meet immunosuppression/non-immunosuppression criteria
• Inability to obtain informed consent from patient
• Previous diagnosis of ASIL or anal/rectal cancer