A 14-month-old girl presented with 6 months of episodic severe diarrhea. Inpatient care for parenteral rehydration and correction of severe hypokalemia was necessary. Routine ultrasound investigation of the abdomen revealed a paravertebral, left-sided mass (Fig. 1). Neuroblastoma was suspected, and magnetic resonance imaging confirmed a solid, calcified tumor located paravertebral near the inferior renal pole. Serum levels of vasoactive intestinal polypeptide (VIP) were extremely elevated (679.5 pg/mL, normal 10–60 pg/mL). After complete resection of the solid tumor (Fig. 2), the girl showed prompt recovery and immediate cessation of diarrhea. Postoperative serum VIP levels returned to normal (18.9 pg/mL). Histology revealed ganglioneuroblastoma with intracellular staining of chromogranin A as a sign of neuroendocrine activity (Fig. 3).FIGURE 1: Abdominal ultrasonography: solid tumor adjacent to the inferior pole of the left kidney.FIGURE 2: Intraoperative view: the whitish and solid tumor is located to the right of the inferior renal pole. The double ureter is marked by yellow vessel loops.FIGURE 3: Immunohistochemical imaging of chromogranin A, appearing as bronze granula in the cytoplasm of tumor cells.Persistent diarrhea in childhood can be the result of paraneoplastic secretion of VIP. This secretory diarrhea leads to extensive electrolyte loss. In contrast to pancreatic VIPomas in adults, VIP-secreting tumors in children are usually of neuroblastic origin, containing ganglioneuroblastoma, ganglioneuroma, neuroblastoma, pheochromocytoma, and neurofibroma (1–4). VIP secretion in these tumors is associated with a favorable outcome of treatment (5,6). Routine use of ultrasound in severe diarrhea led to the diagnosis of a VIP-secreting tumor in our patient. Complete tumor resection is the therapeutic strategy of choice.