Mondo Description High-grade neuroendocrine carcinoma of the corpus uteri is an extremely rare, aggressive, primary uterine neoplasm, originating from neuroendocrine cells scattered within the endometrium, characterized, macroscopically, by a bulky, frequently polypoid, mass with abundant necrosis located in the uterus and, histologically, by rosette-like and cord-like structures consisting of small, rounded cells with oval nuclei and scarce cytoplasm. Patients often present with dysfunctional uterine bleeding, pelvic or abdominal mass and, especially in later stages of the disease, abdominal pain. Symptomatic metastatic spread or symptoms related to a paraneoplastic syndrome, such as retinopathy, or Cushing syndrome due to ectopic ACTH production, may be associated.