Table 1.

Histological assessment of biopsy specimens of colon and rectum and comparison with Vienna classification

Definition of group classification of Japan	Vienna classification
Group X: Inadequate material for histological diagnosis
Group 1: Normal tissue and non-neoplastic lesion	Category 1
Group 2: Lesions in which it is difficult to determine whether the lesion is tumorous or non-tumorous	Category 2
Group 3: Adenoma (benign neoplasia)	Category 3
Group 4: Neoplastic lesion suspected of being carcinoma	Category 4.1
Group 5: Carcinoma	Category 4.1 to 5.2

Japanese classification is used only for biopsy tissue diagnosis (English edition of gastric carcinoma is now being prepared for publication).