What is the definition of a malignant polyp?
Cancer within a polyp through uscualris mucosae into submucosa but not through muscularis propria
How do you assess risk of LN involvement in a malignant polyp?
Estimated via endoscopic, morphological and histological features
What are the endoscopic assessment of polyps? (6)
- Size
- Morphology - Paris classification
- Location
- Lifting sign
- Chromoendoscopy
Kudo pit pattern (7) - NBI NICE calssification (3)
What is the Kudo Pit pattern?
It is white light chromoendoscopy looking at openings of colonic crypts. 7 tier system
1 = normal mucosa
1-4 less likely cancerous
%+ higher risk malignancy
5: irregular mucosa, decrease of loss of pits
Classification of narrow band imaging
NICE classification (NBI international colorectal endoscopic classification)
based on colour, vessels and surface pattern
type 1: hyperplastic, sessile serrated polyps, organized pattern
type 2: adenomas
type 3: deep mucosal invasion. irregular disrupted vessels. amorphous or absent surface pattern.
What are the histological features of interest for a malignant polyp? (6)
- Differentiation
- Size
- Morphological calssification/invasion
- Haggit, Kikuchi
- Margins
- LVI
- Tumour budding
What is tumour budding?
1-4 tumour cells cluster at the advancing edge of the tumour
- low: 0-4 buds
- intermediate: 5-9 buds
- High >10 buds
What is the Haggit classification?
Depth of invasion in a pedunculated polyp
- 0: mucosa only
- 1: head
- 2: neck
- 3: stalk
- 4: base but above muscularis propria
What are some polyp classifications
Benign polyps
- hyperplastic, inflammatory, Juvenile polyps
Neoplastic polyps
- adenomatous
- serrated polyps
What is the Kikuchi system?
Depth of Invasion into submucosa in a sessile polyp
- SM 1: invading top third of submucosa <1000um. (0-3% risk LN)
- SM2: middle third. (8-10% risk LN)
- SM3: deepest third (25% risk LN)
What is the management of malignant polyps?
Balance of risk of residual disease, recurrence, LN involvement against patient comorbidities, risk taking, surgical risk, location of polyp
- MDT approach
- Surveillance,
- Endoscopic
- Surgical resection
