- 4 main types of polyps – hyperplastic, inflammatory, hamartomatous and adenomatous
Hyperplastic polyps
- Most common type
- Very small in size (1-2mm) and multiple
- Most common in the rectum
- Features
- Columnar epithelium
- Cystic dilation
- Goblet cells
- Lymphocytes
- No malignant potential
Inflammatory polyps
- Ulcerative colitis
- Crohn’s disease
- Diverticulitis
Hamartomatous polyps
Peutz-Jegher Polyp
- benign hamartomatous polyps in the GIT and hyperpigmented macules on the lips and oral mucosa
- Hyperpigmented lesions can also occur on forearms, palms, soles, digits
- Clinical features – colicky abdominal pain; intussusception, bleeding, anaemia
Juvenile Polyps
- Occur in infants and young children in rectum and distal colon
- Can be single/multiple
- Usually they are pedunculated (have a stalk)
- Has a familial tendency; most common in male children
- The polyps are vascular and secrete mucus
- There is little malignant potential, but should be endoscopically removed upon discovery
Adenomatous polyps
- Can be tubular, villous or tubulovillous
- Tubular is most common and has the lowest malignant potential
- Villous type has the highest malignant potential
- Adenoma size >2cm has a higher chance of developing carcinoma
- Clinical features – bleeding per anum, anemia, diarrhoea (with mucus discharge, common in villous type)
Familial Adenomatous polyposis (FAP)
- Inherited AD neoplastic condition, presents in a younger age group (15-20 year olds)
- 100s of Adenomatous polyps develop throughout colon and rectum
- Risk of developing carcinoma is approximately 100% within 15 years
- Associated with
- Gardner’s syndrome – FAP with extraintestinal manifestations (osteomas, desmoids tumours and epidermoid cysts)
- Turcot syndrome – FAP with brain tumour (medulloblastoma or glioma)