Prolonged Survival in a Patient with Metastatic Vasoactive Intestinal Peptide Producing Pancreatic Neuroendocrine Tumors

VIPomas are rare neuroendocrine tumors that secrete vasoactive intestinal peptide. They are detected in 1 in ten million people per year. The majority of these tumors arises within the pancreas, but may also arise as other VIP-secreting tumors as in bronchogenic carcinoma, colon carcinoma, ganglioneuroblastoma, pheochromocytoma, hepatoma and adrenal tumors. They are characterized by profound diarrhea, hypokalemia, and achlorhydria and were first described by Verner and Morrison in 1958. It was also named pancreatic cholera as the cholera toxin acts; the Vasoactive Intestinal Peptide (VIP) causes elevation of the cyclic adenosine monophosphate, resulting in intestinal smooth muscle relaxation, inhibition of electrolyte absorption and profound secretory diarrhea. We are reporting a case involving a 42 year old male patient who presented with intermittent attacks of watery diarrhea up to 10 times per day for 3 weeks mostly worsening in the last 3 days prior to seeking medical advice. Stool studies were negative, but patient had hyperglycemia and mild hyponatremia. Further evaluation revealed a pancreatic mass with multiple hepatic focal lesions encountered in abdominal ultrasound and CT scan. Ultrasound guided biopsy revealed metastatic pancreatic endocrine carcinoma with VIP expression. Serum VIP level was elevated to 496 (Normal <100). We report a case of metastatic well-differentiated VIPoma treated mainly with long acting octreotide and streptozocin/5fluorouracil combination showing marked improvement of symptoms, minimal response of the tumor size but more significantly, more than 2 year period survival/follow up in a patient that was not a candidate for surgical resection. Review of literature focused on cases with metastatic VIPoma who were not surgical candidates, but had prolonged survival of more than 2 years disease. We reviewed the different therapeutic options offered for this patient population exploring the response rates, survival and recent recommendations.