Microscopic features of colorectal neoplasia in inflammatory bowel diseases

Table 1 Vienna classification of gastrointestinal epithelial neoplasia

Category
1	Negative for neoplasia/dysplasia
2	Indefinite for neoplasia/dysplasia
3	Non-invasive low-grade neoplasia (low-grade adenoma/dysplasia)
4	Non-invasive high-grade neoplasia
	High-grade adenoma/dysplasia
	Non-invasive carcinoma (carcinoma in situ)1
	Suspicion of invasive carcinoma
5	Invasive neoplasia
	Intramucosal carcinoma2
	Submucosal carcinoma or beyond

Reproduced from Schlemper et al[94].

¹Non-invasive indicates absence of evident invasion;

²Intramucosal indicates invasion into the lamina propria or muscularis mucosae.

Table 2 Biopsy classification of dysplasia in inflammatory bowel disease

Negative for dysplasia	Positive for dysplasia
Normal mucosa	Low-grade dysplasia
Inactive (quiescent) colitis	High-grade dysplasia
Active colitis