Study Objective: To evaluate the usefulness of clinical, ultrasonographic, hysteroscopic, and immunohistochemical parameters in differentiating endometrial polyps from endometrial cancer.Design: Cross-sectional study (Canadian Task Force classification II-2).Setting: Tertiary public hospital, university teaching center.Patients: Eighty-two women who underwent hysteroscopic polypectomy and 20 women who underwent surgery to treat endometrial cancer.Interventions: Analysis of medical records and immunohistochemical assessment of estrogen receptors, progesterone receptors, and endothelial markers CD34 and CD 105.Measurements and Main Results: Among women with endometrial cancer and endometrial polyps, respectively, mean age was 63 and 57 years (p = .01), 89% and 67% were postmenopausal (p < .05), and 85% and 30.5% had postmenopausal bleeding (p < .01). No sonographic parameter enabled differentiation of endometrial polyp from cancer. Of patients with endometrial cancer, 72% exhibited signs suggestive of hyperplasia, and endometrial polyps were diagnosed during hysteroscopy. Estrogen receptors (>= 2 vs >= 1; p < .001) and progesterone receptors (>= 3 vs >= 2; p = .07) were greater in endometrial polyps. There was no significant difference in microvessel density (p > .05).Conclusions: Ultrasonographic parameters and endothelial markers did not enable differentiation of polyps from endometrial neoplasia. Postmenopausal bleeding and endometrial hypervascularization along with vascular atypia at diagnostic hysteroscopy showed a greater association with endometrial cancer. (c) 2014 AAGL. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)