1. General Surgery Unit, Health Unit 5 Pisa, Pontedera Hospital, Pontedera, Italy.
2. Department of Internal Medicine, Health Unit 5 Pisa, Pontedera Hospital, Pontedera, Italy.
3. Department of Internal Medicine, University of Pisa, Pisa, Italy.
4. First Department of Pathology, University of Pisa, Pisa, Italy.