Abstract
Definition of neoplasia and new morphological and behavioral classification of neoplasias listed in WHO's ICD-O were presented. According to this classification, the neoplasias were divided into the following 6 groups
/0…Benign
/1…Uncertain whether benign or malignant (borderline malignancy)
/2…Carcinoma in situ (intraepithelial, non-infiltrating, non-invasive)
/3…Malignant, primary site
/6…Malignant, metastatic site (secondary site)
/9…Malignant, uncertain whether primary or metastatic site
The malignant neoplasias were also graded into the following 5 groups:
1…grade I…Well differentiated
2…grade II…Moderately differentiated
3…grade III…Poorly differentiated
4…grade IV…Undifferentiated, Anaplastic
9…Grade or differentiation not determined, not stated or not applicable.
The process of human carcinogenesis was discussed and the roll of dysplasia was stressed.
