[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Non-neoplastic colonic polyps

# Non-neoplastic colonic polyps

- Lesion

Many colon polyps are not tumours: some are piled-up normal cells, some come from injury, and some are inherited malformations with cancer risk.

Updated Nov 12, 2026

## Key points

- Hyperplastic polyp: small (often under five millimetres), left colon and rectum; serration limited to the upper crypt; no malignant potential.
- Solitary rectal ulcer syndrome: rectal bleeding, mucus and an anterior rectal wall lesion from poor sphincter relaxation and prolapse; fibromuscular hyperplasia of the lamina propria.
- Juvenile polyp: usually under age five, rectum, rectal bleeding; cystic mucin-filled glands in an inflamed lamina propria.
- Juvenile polyposis syndrome: autosomal dominant, SMAD4 or BMPR1A (TGF-β pathway); SMAD4 cases often also have hereditary haemorrhagic telangiectasia; high colorectal cancer risk.
- Peutz–Jeghers syndrome: autosomal dominant STK11; mucocutaneous pigmented macules (lips, buccal mucosa); arborizing polyps with smooth muscle, mostly small bowel; intussusception; high lifetime risk of many cancers.
- Other syndromes: Cowden (PTEN), Cronkhite–Canada (non-hereditary, nail and hair loss), tuberous sclerosis.

## What it is

Intestinal polyps are divided into neoplastic (adenomas) and non-neoplastic types: hyperplastic, inflammatory and hamartomatous. Hyperplastic polyps have no malignant potential but must be told apart from sessile serrated lesions. Inflammatory polyps arise from cycles of injury and repair, as in the solitary rectal ulcer syndrome. Hamartomatous polyps can be sporadic or part of inherited syndromes, several of which carry a high risk of cancer inside or outside the gut.

## Non-neoplastic polyps and polyposis syndromes

| Lesion | Gene or cause | Histology | Cancer risk |
| --- | --- | --- | --- |
| Hyperplastic polyp | Delayed shedding of surface cells | Serrated surface, upper third of crypts only | None |
| [Inflammatory (solitary rectal ulcer)](https://durgical.com/en/conditions/rectal-prolapse/) | Repeated abrasion and prolapse | Erosion, hyperplasia, fibromuscular lamina propria | None |
| [Sporadic juvenile (retention) polyp](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/) | Sporadic | Cystic mucin-filled glands, inflamed stroma | Very low |
| [Juvenile polyposis syndrome](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/) | SMAD4, BMPR1A | Many juvenile polyps; dysplasia possible | High colorectal; also gastric and small bowel |
| [Peutz–Jeghers syndrome](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/) | STK11 | Arborizing smooth muscle with normal epithelium | High: colon, pancreas, breast, lung, ovary, uterus, testis |
| Cowden syndrome | PTEN | Hamartomatous polyps, lipomas, ganglioneuromas | Breast and thyroid; not GI |

## Clinical notes

- Juvenile and Peutz–Jeghers polyps can bleed, prolapse through the anus or lead an intussusception.
- Pigmented macules inside the mouth distinguish Peutz–Jeghers from ordinary freckles.

## Memory aid

Peutz–Jeghers: pigmented lips, polyps with muscle branches, and a long list of cancers.

## Test yourself

Think of the answer, then tap the question to see it.

## Which gene is mutated in Peutz–Jeghers syndrome?

STK11, a tumour suppressor regulating AMP-activated kinase pathways.

## What histologic feature distinguishes a Peutz–Jeghers polyp from a juvenile polyp?

An arborizing network of smooth muscle mixed with lamina propria and normal-looking glands.

## Which genes cause juvenile polyposis syndrome?

SMAD4 and BMPR1A, members of the TGF-β signalling pathway.

## Why must a hyperplastic polyp be distinguished from a sessile serrated lesion?

Hyperplastic polyps have no malignant potential, whereas sessile serrated lesions can progress to cancer.

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## Connections

## Related 6

- [Colonic adenomas and serrated lesions](https://durgical.com/en/general-pathology/colonic-adenomas-and-serrated-lesions/)
- [Hereditary colorectal cancer: FAP and Lynch syndrome](https://durgical.com/en/general-pathology/hereditary-colorectal-cancer-fap-and-lynch-syndrome/)
- [Gastric polyps](https://durgical.com/en/general-pathology/gastric-polyps/)
- [Ulcerative colitis vs Crohn disease](https://durgical.com/en/general-pathology/ulcerative-colitis-vs-crohn-disease/)
- [Hereditary cancer syndromes: the table to know](https://durgical.com/en/general-pathology/hereditary-cancer-syndromes-the-table-to-know/)
- [Tumour suppressor genes: RB, TP53, APC, BRCA and the two-hit hypothesis](https://durgical.com/en/general-pathology/tumour-suppressor-genes-rb-tp53-apc-brca-and-the-two-hit-hypothesis/)

## Related conditions 5

- [Colorectal polyps and hereditary polyposis syndromes (FAP, Lynch)](https://durgical.com/en/conditions/colorectal-polyps-and-hereditary-polyposis-syndromes/)
- [Rectal prolapse](https://durgical.com/en/conditions/rectal-prolapse/)
- [Intussusception (children)](https://durgical.com/en/conditions/intussusception/)
- [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/)
- [Lower gastrointestinal bleeding](https://durgical.com/en/conditions/lower-gastrointestinal-bleeding/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Peutz-Jeghers syndrome: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/peutz-jeghers-syndrome/) (MedlinePlus, US National Library of Medicine, 2025); [Juvenile polyposis syndrome: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/juvenile-polyposis-syndrome/) (MedlinePlus, US National Library of Medicine, 2025).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/non-neoplastic-colonic-polyps/