Clinicopathological characteristics of duodenal microgastrinomas

Duodenal gastrinomas do not seem to behave as malignantly as sporadic pancreatic gastrinomas. Statistical analysis of 49 patients with sporadic pancreatic gastrinoma and 21 patients with sporadic duodenal gastrinoma reported since 1980 in Japan revealed that the incidence of hepatic metastasis was 57% in patients with sporadic pancreatic gastrinoma and only 9% in patients with sporadic duodenal gastrinoma (p less than 0.01). These findings suggest that there is an essential biological differences between duodenal and pancreatic gastrinoma. Five patients with sporadic duodenal microgastrinoma (tumor diameter less than 5mm) in our hospital had no hepatic metastases; however, 4 patients had lymph node metastases. Immunohistochemical study of 5 sporadic duodenal microgastrinomas and 6 sporadic pancreatic gastrinomas revealed that the sporadic duodenal gastrinomas contained significantly fewer insulin-producing or glucagon-producing cells than sporadic pancreatic gastrinomas. The cellular composition of the metastatic lymph nodes from duodenal microgastrinomas was similar to that of the primary tumor. This difference in cellular composition between the duodenal microgastrinomas and the pancreatic gastrinomas suggests that the process of development and differentiation of gastrinoma cells is different.