Verner-Morrison syndrome. Literature review.

Chronic diarrhea in infants is a common condition for addressability to pediatric gastroenterologists. The causes are multiple and the delay in reaching the final diagnosis can lead to complications in the general condition of the child. The purpose of this review is to present the bio-clinical and histogenetic particularities of a rare clinical entity, characterized by tumoral causes of chronic diarrhea. VIPomas are neuroendocrine tumors that autonomously secrete vasoactive intestinal peptide (VIP). Watery diarrhea, hypokalemia and achlorhydria (WDHA) syndrome caused by VIP-producing tumors only rarely occurs in adult patients with non-pancreatic disease. In pediatric patients, it is extremely rare for a VIPoma to originate in the pancreas; instead, WDHA syndrome is usually associated with VIP-secreting neurogenic tumors involving the retroperitoneum or mediastinum. The majority of VIP secreting tumors in pediatric patients are represented by ganglioneuroblastomas or ganglioneuromas originating in the adrenal medulla or sympathetic neural crest. This syndrome of watery diarrhea associated with hypokalemia and achlorhydria was first described by Verner and Morrison, in 1958, and has been assumed to be due to hypersecretion of VIP. In children, as well as in adult patients, the most likely explanation for persistent secretory diarrhea may be an occult VIPoma. In conclusion, the physicians should be aware that there are some rare tumoral causes of chronic diarrhea, often under-diagnosed. If the diagnosis is not considered, extensive gastrointestinal investigations will be undertaken, delaying the diagnosis and avoidable morbidity will occur.