We reviewed 827 consecutive cases of pure endometrial endometrioid adenocarcinoma (EEA) treated by hysterectomy to update the distribution of pathologic features. Tumor grade (reported in a 2-tiered system), depth of myometrial invasion, presence of cervical involvement, lymphovascular invasion (LVI), and evidence of extrauterine disease were recorded.The median age at diagnosis was 62 years (range, 30-94 years). The tumor was high grade in 94 cases (11.4%), invaded into the outer half of the myometrium in 249 (30.1%), was positive for cervical involvement in 171 (20.7%), and was positive for LVI in 182 (22.0%). Lymph nodes (sampled in 85 cases) were positive in 13 (1.6%), and ovarian metastases were present in 15 cases (1.8%). High tumor grade was significantly associated with deep myometrial invasion (P > .0001), cervical involvement (P = .0065), and LVI (P > .0001).EEA manifests most commonly with low tumor grade and without deep myometrial invasion. High tumor grade is significantly associated with deep myometrial invasion, cervical involvement, and LVI.