Sporadic pancreatic vasoactive intestinal peptide-producing tumor (VIPoma) in a 47-year-old male

VIPoma is an exceedingly unusual neuroendocrine neoplasm that autonomously secretes vasoactive intestinal polypeptide (VIP). Its reported incidence is approximately 1 per 10 million individuals per year. Herein, we report the case of sporadic pancreatic VIPoma in a 47-year-old male who presented with a six-month history of chronic, plentiful, watery diarrhea. On physical examination, the patient looked sick, lethargic and had signs of dehydration. Laboratory investigations revealed high VIP hormone level (989 pg/mL), hypokalemia, hypercalcemia, hyperglycemia, high blood urea nitrogen, high creatinine, and metabolic acidosis on arterial blood gas. Contrast-enhanced computed tomography (CT) scan showed a 3.1 × 3.3 × 4.7 cm, well-defined, enhancing lesion involving the pancreatic tail with a cystic component. Moreover, a 5.7 × 6.1 × 6.8 cm metastatic hepatic lesion was identified. The patient underwent distal pancreatectomy with splenectomy, hepatic lesion resection, and lymph node dissection. Histopathological and immunohistochemical examination of the pancreatic and hepatic lesions revealed neuroendocrine tumor (VIPoma). Postoperatively, the patient received radiofrequency ablation for the hepatic lesion. A post-operative six-month follow-up showed significant symptomatic relief, reduced VIP hormone level (71 pg/mL) and normalized electrolyte and acid–base profiles. However, a magnetic resonance imaging (MRI) scan showed a small residual metastatic liver lesion which was considered for hepatic artery embolization (HAE). The patient is still alive with a residual hepatic disease at 18 months. We also present a brief literature review on VIPoma.