polyps

A polyp is a growth that protrudes from a mucous membrane or other surface. In zoology, a polyp refers to one of the life stages of cnidarians, typically sessile and tubular, often reproducing asexually; many corals and sea anemones are polyps. The polyp stage contrasts with the free-swimming medusa.

In medicine, polyps are localized mucosal protrusions arising from the lining of hollow organs such as the nose, sinuses, stomach, intestines, uterus, or cervix. Most are benign but can cause symptoms or complications; some have precancerous potential, especially certain colorectal polyps.

Common types in humans include nasal polyps (soft, noncancerous growths in the nasal passages and sinuses that can cause congestion, reduced sense of smell), and colorectal polyps (growths on the inner lining of the colon or rectum; subtypes include adenomatous, hyperplastic, inflammatory, hamartomatous; adenomatous polyps are more likely to become cancerous). Other polyps include endometrial and endocervical polyps in the uterus, and juvenile polyps in children.

Diagnosis usually involves endoscopy, imaging, or biopsy. Treatment depends on type and symptoms and may include watchful waiting for small asymptomatic polyps, medical therapy to reduce inflammation, or removal through polypectomy during endoscopy or surgery. In the colon, removal reduces colorectal cancer risk, with surveillance colonoscopy recommended after removal.

Prognosis varies by type and location; most mucosal polyps are benign, but certain polyps carry cancer risk if not removed or monitored. Genetic syndromes such as familial adenomatous polyposis can cause numerous polyps and higher cancer risk.