Department of Internal Medicine IV, University-Hospital Campus Grosshadern, Ludwig-Maximilian University of Munich, Munich, Germany. Department of Internal Medicine II, University-Hospital Campus Grosshadern, Ludwig-Maximilian University of Munich, Munich, Germany. Interdisciplinary Center of Neuroendocrine Tumours of the GastroEnteroPancreatic System (GEPNET-KUM), Klinikum der Universitaet Muenchen, Ludwig-Maximilians-University of Munich, Campus Grosshadern, Marchioninistr, 15, 81377, Munich, Germany. Department of Internal Medicine IV, University-Hospital Campus Grosshadern, Ludwig-Maximilian University of Munich, Munich, Germany. christoph.auernhammer@med.uni-muenchen.de. Interdisciplinary Center of Neuroendocrine Tumours of the GastroEnteroPancreatic System (GEPNET-KUM), Klinikum der Universitaet Muenchen, Ludwig-Maximilians-University of Munich, Campus Grosshadern, Marchioninistr, 15, 81377, Munich, Germany. christoph.auernhammer@med.uni-muenchen.de.