Anal cytology has been described as a screening tool to detect abnormal cells in high-risk patients.

Those who are found to have abnormal Papanicolaou smears undergo high-resolution anoscopy with

acetowhitening and staining with Lugol solution and biopsy of any suspicious lesions. Options for

treatment include local destruction (cryotherapy or fulguration), excision, or observation.

AIN is graded on the degree of dysplasia. Low-grade AIN (grade I) rarely undergoes malignant

transformation, and can be observed or ablated if symptomatic. High-grade AIN (grades II and III) is

believed to be the premalignant counterpart of anal squamous cell cancer, however the incidence and

predictability of the progression of AIN to invasive cancer is unclear. Some authors recommend

aggressive destruction or excision of any high-grade lesions, however there is currently no evidence that

removal of high-grade AIN results in a reduction of the risk of anal cancer. Others have therefore

instead recommended that AIN be observed unless there are gross visible lesions or ulcerations present.

HIV and AIDS

Surgery for anorectal diseases is the most common indication for surgery in HIV-infected patients and in

5% of patients their anorectal complaint is the presenting symptom of their HIV infection. Several

studies demonstrated poor wound healing and increased morbidity in the surgical treatment of anorectal

disease in AIDS patients. Delayed or failed wound healing has been associated with presence of AIDS,

absolute leukocyte count, and CD4 count.

Anal fissures that occur in the HIV-positive patient must be distinguished from idiopathic AIDS-related

anal ulcers and ulcerating sexually transmitted diseases such as HSV or syphilis. Anal fissures in this

patient population are indistinguishable from those in the general population and their treatment is

similar – initial conservative management with surgery for treatment failures. Treatment of fissure in

HIV-positive patients also includes controlling diarrhea when possible and encouraging abstinence from

anoreceptive intercourse.

With the increasing use of highly active antiretroviral therapy (HAART), the incidence of AIDS-related

anorectal ulcers has decreased markedly, however they are still found in patients with low CD4 counts.

AIDS-related ulcers typically occur more proximal in the anal canal (frequently above the dentate line),

are broad based with deep ulceration with destruction sphincter planes, and may demonstrate mucosal

bridging. Surgical debridement allows for adequate drainage of feculent or purulent material trapped in

the ulcer and removes necrotic debris. The area should also be biopsied to rule out malignancy.

Intralesional injection with steroids has also been described to decrease pain, however it has not been

demonstrated to affect healing. Perianal suppurative diseases are common conditions in AIDS patients.

Abscesses should be drained using small incisions, and judicious use of draining setons will help lessen

recurrent sepsis. The abscess should also be cultured and broad-spectrum antibiotics should be given.

Kaposi sarcoma, which is associated with the herpesvirus HHV-8, is one of the more common

malignancies in AIDS patients. Found more commonly in patients with low CD4 counts, its incidence has

decreased in the era of HAART therapy. Kaposi sarcoma may occur in the colon or rectum, but may also

be found in the anal canal and perianal skin. Most patients are asymptomatic, however bleeding or

obstruction may rarely occur. Treatment is directed at improving the patient’s CD4 count, however

radiation and chemotherapy have also been employed.

Symptomatic cytomegalovirus (CMV) infection may also occur in profoundly immunocompromised

AIDS patients. CMV can cause proctocolitis that presents with diarrhea, fever, and abdominal pain.

Examination of the mucosa of the rectum demonstrated sharply demarcated hallow ulcers with fibrinous

exudate. Biopsies that demonstrate “owl’s eye” inclusion bodies are diagnostic. Treatment is with

antiviral medications and initiation of HAART therapy.

NEOPLASTIC ANORECTAL DISEASE

Neoplasms of the anal region are relatively rare, and include both benign and malignant tumors.

Important in the diagnosis and management of these conditions is defining the location of the tumor

with reference to landmarks such as the dentate line and anal verge because treatment of tumors of the

anal canal is often significantly different from treatment of tumors of the anal margin. The American

Joint Commission on Cancer has developed standardized terminology and has recognized the anal verge

as the line dividing between the anal canal and anal margin. Although it may be difficult to determine

the exact location of large, bulky tumors that encompass both the anal canal and anal verge, the

location of most tumors of the anal margin can be determined with inspection alone.

1879

Anal Margin Tumors

Bowen Disease (High-Grade AIN)

Although AIN is more common in HIV-positive individuals, high-grade AIN may develop in the perianal

skin of HIV-negative patients. Also referred to as Bowen disease, these lesions tend to grow slowly, and

are more prevalent in older women and immunosuppressed patients.43 While perianal Bowen disease is

often asymptomatic, patients may present with burning or pruritus. Changes seen on examination may

range from thickened erythematous skin to discrete scaly or crusted plaques, often making it difficult to

differentiate from other disorders such as psoriasis or eczema. Biopsy of any atypical anal lesions is

mandatory (Fig. 70-28).

While wide local excision has traditionally been the treatment of choice for Bowen disease, the

understanding that the disease is likely related to HPV infection has changed the treatment paradigm.

Excision should be performed in any patient with intractable itching or burning, those with an atypical

lesion or a lesion than 3 cm, or when biopsy demonstrates invasive squamous cell cancer. Mapping of

the perianal skin with circumferential biopsies will often show residual disease, and evidence that this

practice improves patient outcomes is lacking. As in patients with HIV and AIN, the role of highresolution anoscopy with staining of the perianal skin remains controversial. Although Bowen disease is

a premalignant condition, the rate of malignant transformation in the HIV-negative population is likely

lower than in HIV-positive patients with high-grade AIN. Patients with asymptomatic disease may

therefore be closely observed, with target biopsy of any suspicious areas.

Figure 70-28. Biopsy of any atypical anal lesion. With permission from Bejarano PA, Boutros M, Berho M. Anal Squamous

Intraepithelial Neoplasia. Gastroenterol Clin North Am 2013;42(4):893–912.

Squamous Cell Carcinoma

8 Squamous cell carcinomas (SCCs) located at the anal margin are similar to those that develop

elsewhere in skin. The disease afflicts men and women at an equal rate and tends to present in the

seventh decade of life. Patients often present with a mass, pruritus, rectal pain, or bleeding, and the

gross appearance is typically a mass with central ulceration and rolled, everted edges. While symptoms

may mimic other conditions such as fistula, hemorrhoids, or chronic pruritus, any chronic unhealed or

indurated ulceration in the perianal area should be biopsied (Fig. 70-29). Due to its location, the

diagnosis of perianal squamous cell cancer is often delayed, with more than 50% of cases diagnosed

more than 24 months after the onset of symptoms.44

Treatment of superficial squamous cell cancer of the anal margin that does not invade muscle is local

excision with a 1-cm margin. Radiation or chemoradiation should be considered for large tumors

invading the sphincter and/or radical resection with abdominoperineal resection is another option,

however this procedure has been associated with high failure rates from local recurrence, inguinal

lymph node metastasis, and distant metastasis.45 The prognosis for patients with T1 tumors (those <2

cm) is excellent, with 5-year survival rates approaching 100%. Five-year survival of patients with larger

tumors is variable, depending on the type of treatment.

1880

Figure 70-29. Chronic unhealed or indurated ulceration in the perianal area. Courtesy of Dr. Scott Steele.

Paget Disease

Paget disease is an intraepithelial adenocarcinoma of the perianal skin. While this disease was initially

described in the breast, it may also occur in the axilla and anogenital region. The exact origin of Paget

cells is unknown, however authors have hypothesized that they arise from apocrine or sweat glands, or

are metastatic from an underlying adenocarcinoma. Perianal Paget disease begins as a benign in situ

neoplasm but may eventually become invasive as an adenocarcinoma.

Paget disease is rare disease, and occurs most commonly in elderly patients. The typical appearance is

an erythematous, sometimes sharply demarcated rash that may ooze or scale. Paget disease must be

differentiated from other dermatologic conditions such as eczema, lichen sclerosis, and hyperkeratosis;

these conditions tend to present in a circumferential pattern, whereas Paget disease tends to be

unilateral. The diagnosis is made by biopsy, which demonstrates the presence of periodic acid–Schiff

positive Paget cells (Fig. 70-30). Patients with Paget disease should also undergo a colonoscopy, as

synchronous visceral carcinomas have been found in up to 50% of patients.46

The treatment of perianal Paget disease in the absence of invasive carcinoma is wide local excision.

Because the disease may extend beyond the grossly visible margin, mapping biopsies at least 1 cm from

the edge of the lesion in all four quadrants is recommended. Small lesions may be resected with the

wound left open, however if extensive resection is required, reconstruction may be performed with

advancement or rotational flaps.47

Patients with perianal Paget disease and concomitant rectal adenocarcinoma should undergo

abdominoperineal resection, whereas those with anal cancer should be treated with chemotherapy and

radiation. Patients with invasive Paget disease should undergo APR, however the prognosis is quite

poor as the majority of patients have distant metastases at the time of diagnosis.48 The pattern of

metastasis is similar to that of adenocarcinomas of the distal rectum.

Basal Cell Carcinoma

Basal cell carcinomas of the perianal skin are rare. Similar to basal cell cancers of the skin elsewhere on

the body, these tumors typically appear as an ulcer with irregular and raised edges. This condition is

more common in men than women, and one-third of patients have basal cell cancers on other cutaneous

sites.49 Treatment is wide local excision followed by close surveillance, as recurrence is not uncommon.

1881