Double-balloon enteroscopy in the diagnosis of an adenocarcinoma of the fourth portion of the duodenum: report of a case oleh Adriana Vaz Safatle-Ribeiro, Tomazo Antonio Prince Franzini, Rogerio Kuga, Robson Kioshi Ishida, Elisa Ryoka Baba, Daniel Chaves Mendes, Shinichi Ishioka, Paulo Sakai