Rare uterine malignancies present treatment challenges because of their clinical and biological heterogeneity. Among the rarest of the uterine cancers are leiomyosarcomas, uterine stromal tumors, and the mesonephric-like and serous carcinomas. In this article, we review recent advancements in diagnostic precision, risk stratification, and identification of biomarker-guided therapeutic options for these rare subtypes of uterine tumors. The improved understanding of the molecular profile of these tumors has led to the development of targeted treatment approaches. Further progress will depend on a coordinated, global effort to further characterize these diseases and enroll patients on biomarker-driven clinical trials.