Grade 3 endometrial tumors according to FIGO staging is

The differentiation of a carcinoma, expressed as its grade, is determined by architectural growth pattern and nuclear features. In the International Federation of Gynecology and Obstetrics (FIGO) grading system proposed in 1989, tumors are grouped into three grades: grade 1, 5% or less of the tumor shows a solid growth pattern; grade 2, 6% to 50% of the tumor shows a solid growth pattern; and grade 3, more than 50% of the tumor shows a solid growth pattern. The presence of notable nuclear atypia that is inappropriate for the architectural grade increases the tumor grade by one.Histopathologic degree of differentiation:G1 <5% non squamous or non morular growth patternG2 6%-50% non squamous or non morular growth patternG3 >50% non squamous or non morular growth patternReference: Novak's gynecology; 14th edition; Chapter 35; Uterine cancer