Secretory diarrhea with islet cell hyperplasia and increased immunohistochemical reactivity to serotonin

Two patients with secretory diarrhea and signs and symptoms consistent with the Verner-Morrison syndrome and islet cell hyperplasia are described. Both patients responded well to subtotal pancreatectomies. The morphologic changes in the pancreata were characterized by proliferation of islets associated with periductal and interstitial fibrosis. Immunohistochemical stains demonstrated increased staining for serotonin in islet cells. A few islet cells also stained for vasoactive intestinal polypeptide. The significance of these results is discussed.