These controversies depend on the hypothesis that two different populations could exist in the group of MEN1-gastrinomas, one showing an indolent course even in the presence of metastatic disease (usually in peripancreatic nodes) and another showing rapid tumor progression with hepatic metastatization, independent of the size of the tumors [33,85,86]. The gene discussed is MEN1; the disease is gastrin-producing neuroendocrine tumor.