Duodenal neuroendocrine neoplasms with unexpectedly aggressive behaviour: challenging the “watch and wait” approach

The incidence of duodenal neuroendocrine neoplasms has risen over the past decades as a result of the wide availability of endoscopy and associated expertise. Although it is considered that tumour size greater than 10 mm, higher tumour grade and/or location in relation to the ampulla of Vater represent the main risk factors for local or distant metastases, we describe two cases of well differentiated grade 1 and grade 2 neuroendocrine tumours,...