Colon Polyps (Colonic Adenoma): Classification

Classification of polyps/adenomas of the colon (colonic polyps/colonadenomas) according to the WHO classification:

  • Non-neoplastic polyp
  • Neoplastic epithelial polyp
  • Adenoma with the forms:
    • Tubular adenoma
    • Tubulo-villous adenoma
    • Villous adenoma
  • Adenoma with high-grade dysplasia (precancerous/precancerous).
  • Adenoma with carcinoma
  • Other neoplastic polyps

Colonic polyps

Neoplastic polyps Non-neoplastic polyps Submucosal lesions
Benign adenoma Hyperplastic polyp Lipoma
Tubular adenoma Juvenile polyp Neuroendocrine tumor
Tubolovillous adenoma Peutz-Jeghers polyp Colonic metastasis
Villous adenoma Inflammatory polyp Colitis cystica profunda
Carcinoma in situ Pneumatosis cystoides
Intramocosal carcinoma
Invasive carcinoma

Endoscopic classification of gastrointestinal polyps according to the Paris classification.

Type Description Special features
I polypoid shape
Ip stalked
Is sessile
II flat lesion (flat) < twice the height of adjacent normal mucosa/mucosa (8-2% of all polyps)
IIa flat-elevated
IIb flat-flat
IIc flat-depressed
  • Individual flat lesions are slightly depressed
  • Up to 8% of these polyps are already infiltrated into the mucosa or submucosa from a size of 5 mm (T-carcinomas)
  • From a size of 0 mm is already present in 40% of cases infiltration into deeper layers
III exulcerated, excavated lesion

Vienna classification of gastrointestinal epithelial neoplasms.

Category Description Therapy
1 No neoplasia (new growth) None
2 “Indefinite” for neoplasia Follow-up
3 Low-grade neoplasia of the mucosa (low-grade adenoma/dysplasia). Follow-up/local therapy
4 High grade neoplasia of mucosa Local therapy
4.1. High-grade adenoma/dysplasia Local therapy
4.2. Non-invasive carcinoma (carcinoma in situ). Local therapy
4.3. Intramucosal carcinoma Local therapy
5 Submucosal invasive carcinoma (carcinoma with invasion of the mucosa or deeper) Local/surgical therapy