Nesidioblastosis in Familial Endocrine Adenomatosis

Symptomatic and asymptomatic members of a family with multiple endocrine adenomatosis (MEA) (pancreatic islet, parathyroid, and adrenal cortex) were studied. Of the six subjects studied representing three generations, all had excessive secretion of insulin, three showed excessive plasma glucagon responses to oral administration of dextrose, and four had elevated plasma gastrin levels. This evidence of islet hyperactivity suggests the following: (1) A genetic defect resulted in proliferation of the primordial cell of the islands of Langerhans, a condition termed nesidioblastosis. (2) Neoplastic islet cells have the capacity to secrete insulin, glucagon, and/or gastrinlike peptides. (3) The variable involvement of other endocrine glands in the familial MEA syndrome may be secondary to chronic hypersecretion of one or more of the islet hormones.