Transient Sigmoidorectal Intussusception Simulating Submucosal Tumor in a Healthy Woman: An Unusual Case and Review of the Literature

A 42-year-old healthy woman underwent scheduled polypectomy. The introduction of colonoscope showed a rectal regular subepithelial mass with an aperture on the top but the passage of the endoscope was impossible. By introducing gastroscope, however, the mass had disappeared. Subsequently, an uneventful colonoscopy was performed with resection of three small polyps located in ascending and transverse colon. Transient sigmoidorectal...