n, pl  -mas  or  -ma*ta   :  a neoplasm that often involves blood vessels, usu. occurs in the pancreas or the wall of the duodenum, and produces excessive amounts of gastrin which stimulates gastric-acid secretion and consequent formation of ulcers esp. in the duodenum and the jejunum - see ZOLLINGER-ELLISON SYNDROME  .
 
 
 
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