Ganglioneuromas (GN) are rare, benign neurogenic tumors that arise from sympathetic ganglia. They are often asymptomatic. However, in rare cases, they may secrete catecholamines, vasoactive intestinal polypeptides (VIP), or androgenic hormones and manifest with flushing, symptoms of catecholamine excess or chronic diarrhea. We report a young Saudi girl with chronic secretory diarrhea, severe hypokalemia and abdominal distension. After an extensive work up, a well-defined hypodense heterogeneous mediastinal mass was noted in radio imaging. A complete recovery was seen after surgical removal of that mediastinal mass which turned to be a ganglioneuroma.