Somatic endometrial carcinomas with trophoblastic components have only rarely been described. To better characterize this distinctive combination of histotypes, we report herein 4 new cases, representing the largest cohort reported thus far, and review previously reported cases. The 4 new patients ranged in age from 61 to 77 yr (mean, 68 yr). The first patient had a grade 2 endometrioid carcinoma, surgical International Federation of Gynecology and Obstetrics stage IA, that recurred 5 months later at the vaginal apex with purely choriocarcinoma elements, suggestive of unsampled trophoblastic areas in the uterus. The 3 other patients were all International Federation of Gynecology and Obstetrics stage III, and included 2 cases of dedifferentiated endometrial carcinoma with 40% and 20% choriocarcinoma components, and 1 case of grade 1 endometrioid carcinoma with a 40% choriocarcinoma component. Postoperative serum β-human chorionic gonadotropin was elevated in all patients. All received adjuvant combination chemotherapy, but all were dead of disease with distant metastases at an average of 11.75 mo (range, 7–16 mo) after primary staging. Data from our cases were combined with those from 24 cases that had previously been reported in the literature between 1972 and 2016. Analysis of this combined data indicates that endometrial carcinoma with trophoblastic component is a rare neoplasm that occurs primarily in postmenopausal patients. The trophoblastic component is most commonly a choriocarcinoma and the somatic component is most commonly an endometrioid carcinoma or an adenocarcinoma/carcinoma reported without further specification; the somatic component may be a diverse array of histotypes or histotype admixtures. Serum and/or urine β-human chorionic gonadotropin is elevated in almost all patients, and fluctuations of β-human chorionic gonadotropin generally correlated with tumor relapses or recurrences. The stage distribution and patient outcomes in the current and previously reported patients suggests that trophoblastic differentiation usually, but not invariably denotes clinical aggressiveness.