Background: Endometrial dedifferentiated carcinoma (DC) is a rare histological subtype with an unclear clinical outcome. Materiasl and Methods: The authors conducted a pathological review of patients with endometrial endometrioid carcinoma treated in this hospital between 1990 and 2013 according to 2014 World Health Organization criteria. They systematically reviewed PubMed literature and the present case concerning the clinical features of DC. Results: One (0.25%) of 375 DC patients was identified. A PubMed search detected 46 patients in 13 studies. Stage information was detailed in 45 patients, as follows: 9 (20%) Stage I, 5 (11%) Stage II, 10 (22%) Stage III, and 21 (47%) Stage IV. Surgical details were reported for 12 patients; 7 (58%) with complete resection, and 5 (42%) with incomplete resection. Early stage and complete resection improved overall survival (p < 0.01, p = 0.02, respectively). Conclusion: DC is a rare and aggressive histological subtype. Further research is needed to investigate new treatment strategies for DC.