Pancreatic gastrinoma

Sustained acid hyperscretion, due either (usually) to a duodenal or pancreatic gastrinoma, or to multiple endocrine adenomata, responds well to proton pump inhibition, often requiring high doses. Resection should always be considered as a cure for those with solitary adenomata, as should operation to reverse the retained antrum syndrome (partial gastrectomy where the antrum is inadvertently retained and isolated from acid inhibition, and secretes gastrin continuously). 

Figure 13.15 shows a 48 year old patient with clinically confirmed NECLM (pancreatic gastrinoma, WHO Type 2). The first post-therapy bremsstrahlung scan is shown on the left hand side of Fig. 13.15 the bremsstrahlung scan after completion of four therapy cycles is shown on the right hand side of the figure. 

FIGURE 10.39 A, Pancreatic gastrinoma (H E stain). B, Immuno-peroxidase stain for gastrin shows weak cytoplasmic staining. 

Atrophic gastritis Pernicious anemia Vagotomy HetfcobactBr py/oW Duodenai/pancreatic gastrinoma Renal faiiure Proton pump inhibitors... 

L7, Larsson, L.-I., Ljungberg, O., Sundler, F., Svensson, S. O., Rehfeld, J. F., Stadil, F., and Holst, J. J., An antropyloric gastrinoma associated with pancreatic nesidioblastosis and islet proliferation. Virchows Arch. A Pathol. Anat. 360, 305-314 (1973). 

Eew studies have been done on the molecular features of gastrointestinal endocrine tumors. Allelic loss of llq has been detected in GI endocrine tumors associated with MENl, and LOH of 1 Iq is also present in a subset of sporadic GI endocrine tumors. Mutations of the MENl gene are present in approximately 30% of sporadic gastrinomas and in occasional midgut and hindgut endocrine tumors. In contrast to pancreatic endocrine tumors, the CpG island methylator phenotype is frequent in GI endocrine tumors. Beta-catenin exon 3 mutations are relatively common (38%) in these tumors, and up to 80% of the tumors show nuclear and cytoplasmic localization of the corresponding protein. Other studies, however, reported absence of exon 3 mutations, but nuclear f5-catenin was found in 30% of cases. In contrast, extra-GI endocrine tumors were negative for nuclear f5-catenin. 

Pancreatic endocrine neoplasms (PENs) are the majority of the endocrine neoplasms in the pancreas.Most PENs are sporadic. However, these tumors also constitute one of the major components of the multiple endocrine neoplasia I (MENl) syndrome or may arise in patients with vHL syndrome. Those that are associated with increased serum levels of hormones and lead to corresponding symptoms are referred to as functional and are named according to which hormone they secrete (e.g., insulinoma—42% of all functional variants, gastrinoma—24%, glucagonoma—14%,... 

Fig. 3.11. Dual phase MDCT of gastrinoma. Axial CT obtained during the pancreatic phase of enhancement (left) shows 1.5 cm hyper-vascular pancreatic isulinoma (arrow). During the portal venous phase (right) the tumor is iso-attenuating (arrow)...

Gastrin-producing cells are not evident in the adult pancreas, yet gastrinomas were previously considered to be predominantly pancreatic endocrine tumors. Currently, it is apparent that at least 50% of the lesions occur in the duodenum. In much the same fashion as carcinoid tumors, the majority of lesions are metastatic or multiple at diagnosis. 

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