Affiliation: | (1) Department of Gastroenterology, University Hospital Leiden, Leiden, The Netherlands;(2) Department of Pathology, University of Leiden, Leiden, The Netherlands;(3) Department of Radiology, Leiden, The Netherlands;(4) Department of Surgery, University Hospital Leiden, Leiden, The Netherlands;(5) Present address: Department of General Internal Medicine, University Hospital Leiden, P. O. Box 9600, 2300 RC Leiden, The Netherlands |