Traditional (type I/II) classification of endometrial carcinoma and relationship to histomorphologic and molecular classification

The traditional classification system (type I/II) of endometrial carcinoma, although helpful in providing a conceptual framework for understanding endometrial carcinoma, does not capture the biological diversity or diversity of clinical outcomes of some histotypes (eg, grade 3 endometrioid cancers, mixed ECs) which do not always fit neatly into one of the two categories.

The thickness of the lines between boxes indicates the percentage of type I or type II carcinomas that are of the corresponding molecular subtypes below. Note that grade 3 endometrioid endometrial carcinoma is considered to be type I by some authors and type II by others and has therefore been left separate from either of these categories.