1. Gastrointestinal Endoscopy Service, Gastroenterology Department, Clinics Hospital, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
2. Surgical Division, Gastroenterology Department, Clinics Hospital, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
3. Pathology Department, Clinics Hospital, University of Sao Paulo School of Medicine, Sao Paulo, Brazil