Anal polyp

What is an anal polyp?

An anal polyp is a benign mucosal growth in the anal canal or the lower part of the rectum (Figure 1). Most often these polyps are inflammatory in nature (arising as a result of chronic irritation), hyperplastic (formed during the process of mucosal cell division) or adenomatous (with potential for malignant transformation). In clinical practice, the term “anal polyp” sometimes also denotes a hypertrophied (enlarged) anal papilla or mucosal elevation associated with a chronic anal fissure.

Why do anal polyps develop?

The main factors contributing to the development of an anal polyp are:

• chronic irritation (for example, constipation or frequent diarrhoea);
• chronic inflammatory processes in the anal canal;
• hemorrhoidal disease;
• inadequate hygiene or excessive mechanical irritation;
• dietary factors (low fibre intake);
• genetic predisposition (especially in cases of adenomatous polyps).

How is an anal polyp diagnosed?

The diagnosis is established based on clinical findings – by performing a digital rectal examination and proctoscopy (instrumental examination). The final diagnosis (type of polyp) is established after histological (microscopic) examination of the polyp, which is performed after its surgical removal.

What are the symptoms of an anal polyp?

Small polyps usually do not cause complaints, but larger lesions are more often traumatised during defecation and may cause the corresponding symptoms:

• bleeding from the rectum (usually fresh blood);
• mucous discharge;
• discomfort or a foreign-body sensation in the rectum;
• itching in the anal area;
• during defecation, prolapse of the lesion from the anal canal may be felt.

What are the complications of an anal polyp?

Polyps of the anal canal may cause complications related to their location or size – fecal incontinence, pain (if inflammation has developed), bowel movement disorders.
Although most anal canal polyps are benign, adenomatous polyps nevertheless carry a risk of malignant transformation (Figure 2).

What treatment is used?

Very small polyps (<5mm) may be observed by performing regular proctoscopy 1x per year. In other cases, surgical removal of the polyp, or polypectomy, is nevertheless recommended. The operation is performed using a perineal approach – this can be provided for polyps located up to 8cm from the anal verge. Polyps located higher require endoscopic treatment. After surgery, histological evaluation of the polyp is important, as it may influence the subsequent observation or treatment plan.

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