Describe Rectal Polyps in detail.

The Concept

Rectal (and colonic) polyps are protruding growths arising from the mucosa. Their great importance is that some are premalignant, so identifying and removing them can prevent colorectal cancer. The key is to distinguish neoplastic (adenomatous) polyps from non-neoplastic ones.

Types

• Neoplastic (adenomatous) polyps — tubular, tubulovillous or villous — are premalignant and give rise to cancer through the adenoma–carcinoma sequence; the villous adenoma carries the highest malignant risk and may secrete mucus, causing mucoid diarrhoea and hypokalaemia.
• Non-neoplastic polyps — hyperplastic, inflammatory, and hamartomatous (juvenile polyps, Peutz–Jeghers) — have low or no malignant potential.

Clinical Features & Management

Polyps may be asymptomatic or cause rectal bleeding, mucus discharge, or prolapse of the polyp. They are diagnosed and treated at colonoscopy, which allows both biopsy and polypectomy. Because adenomas are premalignant, all such polyps are removed and sent for histology, and patients are entered into a surveillance programme — the basis of colorectal cancer prevention.

A Note on Polyposis Syndromes

Beyond isolated polyps, certain inherited polyposis syndromes are high-yield. Familial adenomatous polyposis (FAP) — hundreds to thousands of adenomatous polyps carpeting the colon — carries a near-100% risk of colorectal cancer if untreated, requiring prophylactic colectomy. Peutz–Jeghers syndrome features hamartomatous polyps with mucocutaneous pigmentation. Recognising that multiple polyps or a strong family history may indicate such a syndrome (needing genetic counselling and surveillance) is an important extension of the polyp topic.

The Bottom Line

Rectal polyps matter because adenomatous (neoplastic) polyps are premalignant via the adenoma–carcinoma sequence, so all are removed at colonoscopy with histology and surveillance, and multiple polyps may indicate a polyposis syndrome.

A Note on the Adenoma–carcinoma Sequence

The concept underpinning polyp management is the adenoma–carcinoma sequence — the stepwise accumulation of genetic mutations by which a normal mucosa progresses through adenoma → dysplasia → invasive carcinoma over years. This slow progression is precisely what makes colonoscopic detection and removal of adenomas so effective at preventing colorectal cancer, and it is the rationale for both screening programmes and post-polypectomy surveillance. Larger, villous and more dysplastic adenomas carry the greatest risk and warrant the closest follow-up.

A Note on the Malignant Potential BY Type

It is worth being precise about which polyps carry risk. Villous adenomas have the highest malignant potential (greater than tubular adenomas), and risk also rises with increasing size (especially >1 cm), the degree of dysplasia, and the number of polyps. Hyperplastic polyps, by contrast, are generally benign. This gradation is why the histology of every removed polyp matters, and why patients with larger, villous or numerous adenomas are placed on shorter-interval surveillance than those with small, single tubular adenomas.

Villous adenomas carry the highest malignant risk.

• Rectal/colonic polyps = mucosal protrusions; some are premalignant, so removal prevents colorectal cancer.
• Neoplastic (adenomatous — tubular/villous): premalignant (adenoma–carcinoma sequence); villous adenoma = highest risk, may cause mucoid diarrhoea + hypokalaemia.
• Non-neoplastic: hyperplastic, inflammatory, hamartomatous (juvenile, Peutz–Jeghers).
• Present with bleeding, mucus, prolapse; colonoscopy for diagnosis + polypectomy + histology; remove all adenomas and enter surveillance.