Vasoactive Intestinal Peptide-Producing Neuroblastic Tumors: A Rare Cause of Refractory Diarrhea

Neuroblastic tumors are the most common malignant extracranial solid tumors of childhood. A small subgroup presents chronic incoercible diarrhea due to the tumor's production of vasoactive intestinal peptide (VIP). The hypothesis of an occult tumor is not always considered, which delays and impairs treatment. We aim to identify these patients' characteristics and help alert health professionals to the hypothesis of a neuroblastic tumor in children with chronic diarrhea refractory to the usual approach. We carried out an epidemiological study on all retrievable reports of neuroblastic tumors between 1975 and 2021 described in the Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica database (EMBASE), and Latin American & Caribbean Health Sciences Literature (LILACS) databases. Patient information was divided into categories, and we performed a descriptive analysis. We analyzed 96 cases; 83 (86.5%) cases had diarrhea prior to the diagnosis of the neoplasm, 49 (51%) were ganglioneuroblastomas, 69 (71.8%) were abdominal, and 59 of the 60 patients (98%) with reported acid-base disorders had hypokalemia. When serum VIP was reported, the majority of values varied between one and 20 times the upper reference limit. Seventy-two (75%) patients underwent complete tumor resection, and the overall survival rate was 70%. Serum VIP production by neuroblastic tumors is related to cell differentiation and better prognosis. Such children often require intensive hospital support to reverse the malnutrition and acid-base disorders related to this paraneoplastic syndrome. Its early diagnosis and treatment significantly change the prognosis and quality of life. We, therefore, suggest screening for neuroblastic tumors when health professionals encounter unmanageable chronic secretory diarrhea in children with no defined etiology in the usual investigations.