Primary nodal gastrinomas.

Abstract

The term primary lymph node gastrinoma was first used to describe a group of patients with gastrin-producing tumors present in lymph nodes located in a well-defined anatomic region. The patients had no known primary tumors in the pancreas or gastrointestinal tract and had disease-free survival for up to 18 years. The anatomic region in question has a triangular shape that extends from the cystic and common bile ducts to the second and third portion of the duodenum and the neck and body of the pancreas. The term gastrinoma triangle was coined to identify the area; in addition, it was postulated that lymph nodes located in the gastrinoma triangle normally contained neuroendocrine cells capable of secreting gastrin and other neuropeptides. From its inception, the postulate became the subject of controversy. To extend previous observations, we examined the lymph nodes located in the gastrinoma triangle of 20 autopsy cases for the presence of neuroendocrine cells, as determined by immunohistochemistry, using antibodies to a panneuroendocrine substance (eg, synaptophysin) and a specific neuropeptide (eg, gastrin). Scanning for positive cells was performed by 2 observers (M.E.H. and M.C.C.). We compared the findings in these lymph nodes with lymph nodes obtained from axillary and inguinal dissections during surgical procedures. In all, 417 lymph nodes were studied. Five of the 20 gastrinoma triangle cases contained synaptophysin reactive cells, whereas 3 had gastrin reactive cells. None of the axillary and inguinal lymph nodes contained neuroendocrine cells. Our findings support the hypothesis of entrapment of neuroendocrine cells during development and the presence of primary nodal gastrinomas.