1. Gastrointestinal Endoscopy Unit, Gastroenterology Department, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
2. Surgery Division, Federal University of Rio Grande do Norte, Natal, Brazil
3. Gastroenterology, Hepatology and Endoscopy Division – Harvard Medical School, Brigham and Women’s Hospital, Boston, Massachusetts, USA