1 Digestive Endoscopy Unit, University Hospital of Pisa, Pisa, Italy. . dario.gambaccini@gmail.com.
2 Gastrointestinal Unit, Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi (SA), Italy. dr.luigiruggiero@gmail.com.
3 Digestive Endoscopy Unit, University Hospital of Pisa, Pisa, Italy. e.marciano@ao-pisa.toscana.it.