Anal Pap smears similar to those used in cervical cancer screening have been studied for early detection of anal cancer in high-risk individuals. In 2011, the HIV clinic implemented a program to enhance access to anal cancer screening for HIV-positive men. Nurse practitioners perform anal Papanicolaou screening, and men with abnormal results receive further evaluation with high-resolution anoscopy. The program has helped identify many precancerous growths, allowing them to be safely removed.

Depending on several factors and the location of the infection, CIN can start in any of the three stage, and can either progress, or regress. The grade of squamous intraepithelial lesion can vary.

CIN is classified in grades:

Since many, if not most, anal cancers derive from HPV infections, and since the HPV vaccine before exposure to HPV prevents infection by some strains of the virus and has been shown to reduce the incidence of potentially precancerous lesions, scientists surmise that HPV vaccination may reduce the incidence of anal cancer.

On 22 December 2010, the U.S. Food and Drug Administration approved Gardasil vaccine to prevent anal cancer and pre-cancerous lesions in males and females aged 9 to 26 years. The vaccine has been used before to help prevent cervical, vulvar, and vaginal cancer, and associated lesions caused by HPV types 6, 11, 16, and 18 in women.

Treatment for CIN 1, which is mild dysplasia, is not recommended if it lasts fewer than 2 years. Usually when a biopsy detects CIN 1 the woman has an HPV infection which may clear on its own within 12 months, and thus it is instead followed for later testing rather than treated.

Treatment for higher grade CIN involves removal or destruction of the neoplastic cervical cells by cryocautery, electrocautery, laser cautery, loop electrical excision procedure (LEEP), or cervical conization. Therapeutic vaccines are currently undergoing clinical trials. The lifetime recurrence rate of CIN is about 20%, but it isn't clear what proportion of these cases are new infections rather than recurrences of the original infection.

Surgical treatment of CIN lesions is associated with an increased risk of infertility or subfertility, with an odds ratio of approximately 2 according to a case-control study.

The treatment of CIN during pregnancy increases the risk of premature birth.

Anal sac adenocarcinomas are often suspected due to location (palpable masse in anal sac) and behavior, but a biopsy and histopathology is necessary for a definitive diagnosis. Fine needle aspiration and cytology is a common first step. Cytopathology reveals clusters of cells with uniform round nuclei. These cells do not have many of the features usually associated with malignancy, such as a high nucleus to cytoplasm ratio or prominent nucleoli. Ultrasonography and radiography are performed to look for metastasis.

Aggressive surgical removal of the tumor and any enlarged sublumbar lymph nodes is essential for treatment of the tumor and associated hypercalcaemia. There is a high recurrence rate, although removal of lymph nodes with metastasis may improve survival time. Radiation therapy and chemotherapy may be helpful in treatment. Severe hypercalcaemia is treated with aggressive IV fluid therapy using sodium chloride and medications such as loop diuretics (increased kidney excretion of calcium) and aminobisphosphonates (decreased calcium release from bones). A poorer prognosis is associated with large tumor size (greater than 10 cm), hypercalcaemia, and distante metastasis. Early, incidental diagnosis of small anal sac masses may lead to a better prognosis with surgery alone (ongoing study).

Anal dysplasia is most commonly linked to human papillomavirus (HPV), a usually sexually-transmitted infection. HPV is the most common sexually transmitted infection in the United States while genital herpes (HSV) was the most common sexually transmitted infection globally.

Since 80% of grey horses will develop a melanoma tumor at some point in their lives, it is important to know what kind of treatments are available. There are several treatment options when a horse is found to have a melanoma tumor including surgical or injections:

While most cases require no treatment, therapy options include cryotherapy, application of a topical salicylic acid compound, surgical and laser ablation.

An important anatomic landmark in anal cancer is the pectinate line (dentate line), which is located about 1–2 cm from the anal verge (where the anal mucosa of the anal canal becomes skin). Anal cancers located above this line (towards the head) are more likely to be carcinomas, whilst those located below (towards the feet) are more likely to be squamous cell carcinomas that may ulcerate. Anal cancer is strongly associated with ulcerative colitis and the sexually transmissible infections HPV and HIV. Anal cancer may be a cause of constipation or tenesmus, or may be felt as a palpable mass, although it may occasionally present as an ulcerative form.

Anal cancer is investigated by biopsy and may be treated by excision and radiotherapy, or with external beam radiotherapy and adjunctive chemotherapy. The five-year survival rate with the latter procedure is above 70%.

Anal dysplasia is a pre-cancerous condition which occurs when the lining of the anal canal undergoes abnormal changes. It can be classified as low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL).

Most cases are not associated with symptoms, but people may notice lumps in and around the anus.

The surgical removal of a melanoma tumor is performed when the tumors are small; this prevents the tumors from spreading to the surrounding areas.

Verruciform xanthoma is uncommon, with a female:male ratio of 1:1.1

Colorectal cancer is a disease of old age: It typically originates in the secretory cells lining the gut, and risk factors include diets low in vegetable fibre and high in fat. If a younger person gets such a cancer, it is often associated with hereditary syndromes like Peutz-Jegher's, hereditary nonpolyposis colorectal cancer or familial adenomatous polyposis. Colorectal cancer can be detected through the bleeding of a polyp, colicky bowel pain, a bowel obstruction or the biopsy of a polyp at a screening colonoscopy. A constant feeling of having to go to the toilet or anemia might also point to this kind of cancer.

Use of a colonoscope can find these cancers, and a biopsy can reveal the extent of the involvement of the bowel wall. Removal of a section of the colon is necessary for treatment, with or without chemotherapy. Colorectal cancer has a comparatively good prognosis when detected early.

Differential diagnosis includes seborrheic keratosis, verruca simplex, condyloma acuminatum, granular cell myoblastoma, vulvar intraepithelial neoplasia, bowenoid papulosis, erythroplasia of Queyrat, and verrucous carcinoma

A squamous cell papilloma is a generally benign papilloma that arises from the stratified squamous epithelium of the skin, lip, oral cavity, tongue, pharynx, larynx, esophagus, cervix, vagina or anal canal. Squamous cell papillomas are a result of infection with human papillomavirus (HPV).

The DDx for an individual believed to have Buschke–Ollendorff syndrome is the following:

- Melorheostosis

- Sclerotic bone metastases.

The diagnosis of this condition can be ascertained via several techniques one such method is genetic testing, as well as:

- X-ray

- Ultrasound

- Histological test

Erythroplasia of Queyrat is a squamous-cell carcinoma of the glans penis (head of the penis) or inner prepuce (foreskin) in males, and the vulvae in females. It mainly occurs in uncircumcised males, over the age of 40. Erythroplasia of Queyrat may also occur on the anal mucosa or the oral mucosa.

Some sources state that this condition is synonymous with Bowen's disease, however generally speaking Bowen's disease refers to carcinoma in situ of any location on the skin such as the lower leg. Like Bowen's disease, erythroplasia of Queyrat is associated with human papillomavirus 16 and is a precursor for invasive squamous-cell carcinoma.

It is named for French dermatologist Louis Queyrat (1856-1933), who was head of the dermatology service of l'Hôpital Ricord, a venereal hospital in Paris, now Hôpital Cochin.

Studies have found heightened HPV in mouth cell samples from people with squamous cell carcinoma of the mouth. Studies have not found significant HPV in mouth cells after sampling with toothbrushes (5 of 2,619 samples) and cytobrushes (no oral transmission found).

According to the National Cancer Institute, “The most common test detects DNA from several high-risk HPV types, but it cannot identify the type(s) that are present. Another test is specific for DNA from HPV types 16 and 18, the two types that cause most HPV-associated cancers. A third test can detect DNA from several high-risk HPV types and can indicate whether HPV-16 or HPV-18 is present. A fourth test detects RNA from the most common high-risk HPV types. These tests can detect HPV infections before cell abnormalities are evident.

“Theoretically, the HPV DNA and RNA tests could be used to identify HPV infections in cells taken from any part of the body. However, the tests are approved by the FDA for only two indications: for follow-up testing of women who seem to have abnormal Pap test results and for cervical cancer screening in combination with a Pap test among women over age 30.”

In April 2011, the Food and Drug Administration approved the cobas HPV Test, manufactured by Roche. This cervical cancer screening test “specifically identifies types HPV 16 and HPV 18 while concurrently detecting the rest of the high risk types (31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68).”

The cobas HPV Test was evaluated in the ATHENA trial, which studied more than 47,000 U.S. women 21 years old and older undergoing routine cervical cancer screening. Results from the ATHENA trial demonstrated that 1 in 10 women, age 30 and older, who tested positive for HPV 16 and/or 18, actually had cervical pre-cancer even though they showed normal results with the Pap test.

In March 2003, the U.S. Food and Drug Administration (FDA) approved the Hybrid Capture 2 test manufactured by Qiagen/Digene, which is a "hybrid-capture" test as an adjunct to Pap testing. The test may be performed during a routine Pap smear. It detects the DNA of 13 "high-risk" HPV types that most commonly affect the cervix, it does not determine the specific HPV types. Hybrid Capture 2 is the most widely studied commercially available HPV assay and the majority of the evidence for HPV primary testing in population-based screening programs is based on the Hybrid Capture 2 assay.

The recent outcomes in the identification of molecular pathways involved in cervical cancer provide helpful information about novel bio- or oncogenic markers that allow monitoring of these essential molecular events in cytological smears, histological, or cytological specimens. These bio- or onco- markers are likely to improve the detection of lesions that have a high risk of progression in both primary screening and triage settings. E6 and E7 mRNA detection PreTect HPV-Proofer (HPV OncoTect) or p16 cell-cycle protein levels are examples of these new molecular markers. According to published results, these markers, which are highly sensitive and specific, allow to identify cells going through malignant transformation.

In October 2011 the US Food and Drug Administration approved the Aptima HPV Assay test for RNA created when and if any HPV strains start creating cancers (see virology).

The vulva/vagina has been sampled with Dacron swabs and shows more HPV than the cervix. Among women who were HPV positive in either place, 90% were positive in the vulvovaginal region, 46% in the cervix.

Digestive system neoplasms are tumors which affect the digestive system. Types include:

- esophageal cancer

- gastric cancer

- small intestinal cancer

- colorectal cancer

- anal cancer

Diagnosis is by rectal examination. A specialized tool called a "Perineocaliper" can be used to measure the descent of the perineum. A retro anal ultrasound scan may demonstrate the condition. "Anti sagging tests", whereby the abnormal descent is corrected temporarily, may help to show whether symptoms are due to descending perineum syndrome or are in fact due to another condition.

Normally, the anal margin lies just below a line drawn between the coccyx (tailbone) and the pubic symphysis. In descending perineum syndrome the anal canal is situated several cm below this imaginary line, or it descends 3–4 cm during straining.

Defecography may also demonstrate abnormal perineal descent.

Multiple disorders are found in patients with radiation enteropathy, so guidance including an algorithmic approach to their investigation has been developed. This includes a holistic assessment with investigations including endoscopies, breath tests and other nutritional and gastrointestinal tests. Full investigation is important as many cancer survivors of radiation therapy develop other causes for their symptoms such as colonic polyps, diverticular disease or hemorrhoids.

Giant condyloma acuminatum (also known as a Buschke–Löwenstein tumor and "Giant condyloma of Buschke–Löwenstein tumor") is a rare cutaneous condition characterized by an aggressive, wart-like growth that is a verrucous carcinoma. It is attributed to human papillomavirus.