Intussusception induced by villous tumor of the colon: sonographic findings.

We report a case of intussusception caused by a villous tumor of the ascending colon in an 82-year-old man. Abdominal sonography showed intussusception in the ascending colon, with a transverse scan demonstrating a multiple concentric ring sign. Color Doppler sonography showed blood flow signals in a mass, which was considered to be the lead point of the intussusception. A spontaneous reduction of the intussusception occurred during the examination; sonography then showed a mildly echogenic, mass. The graded compression method revealed that the mass was soft and immobile. Colonoscopy confirmed the diagnosis of villous tumor. Sonography helped to make an early diagnosis, allowing successful conservative management of the tumor and the intussusception.