Fertility-preserving treatment with progestin may be considered in nulliparous women with well-differentiated endometrial carcinoma. Recently, assisted reproductive treatments have been performed to achieve a rapid pregnancy in such cases. This report evaluates a 39-year-old woman who admitted with menorrhagia and primary infertility. Owing to persistent menstrual irregularity and thick endometrium, a diagnostic office hysteroscopy with endometrial biopsy was performed and revealed a well-differentiated adenocarcinoma. Although the woman wished to retain her childbearing potential with conservative management followed by an assisted reproduction cycle, the repeated endometrial biopsies during progestin treatment revealed persistent adenocarcinoma. Complementary surgery was performed due to persistent endometrial malignancy, which noted well-differentiated endometrioid adenocarcinoma without myometrial invasion or extrauterine disease. A review of cases with endometrial carcinoma that have been treated with conservative management and a subsequent assisted cycle is also presented here. To date, there are 14 such reports, including 15 women and 21 healthy infants. However, obtaining remission and maintaining the reproductive capability may not always be possible, even in early-stage cases. Therefore, patient and physician should always consider carefully if fertility-preserving management is preferred after diagnosis of endometrial carcinoma.