MON-341 Pancreatic Vasoactive Intestinal Peptide Tumor (VIPoma) Presenting as Chronic Watery Diarrhea Detected at an Earlier Stage: A Case Report

Abstract

Background: VIPoma is a rare neuroendocrine neoplasm that autonomously secretes vasoactive intestinal peptide. It is a syndrome of watery diarrhea, hypokalemia and achlorydia. Majority of VIPOmas have metastasized at the time of diagnosis. ¹ Case: We report a case of a 36 year-old male initially presenting with non-pruritic, maculopapular rashes over the facial area. Upon consult with a primary care physician, he was prescribed with doxycycline. Few days after the intake of medication, he developed non-bloody, non-mucoid loose watery stools with increasing frequency during the subsequent days. Diarrhea was initially attributed to doxycycline. Hence, it was discontinued. However, despite its discontinuation, the previously noted watery diarrhea persisted for the next three months. This was accompanied by persistent hypokalemia despite sufficient electrolyte correction. On work up, thyroid function test and 5HIAA level were unremarkable. VIP level was elevated at 320 pg/mL (normal < 75 pg/mL). CT scan of the whole abdomen revealed a heterogeneously enhancing pancreatic tail mass measuring 4.0 x 6.6 x 4.1cm. Distal pancreatectomy with peripancreatic lymph node dissection and splenectomy were subsequently done. Frozen section revealed well-differentiated pancreatic neuroendocrine tumor. Immunohistochemical stains were positive for chromogranin and synaptophysin with 1% ki-67. Final staging for the VIPoma were as follows: WHO and ENETS histological classification low grade, G1; AJCC staging for PNET stage 1B; ENETS Classification Stage IIB. The patient’s aforementioned symptoms completely resolved post-operatively. Conclusion: The diagnosis of VIPoma is usually delayed due to its nonspecific manifestations. If it is left untreated, it may lead to renal failure and death. Hence, there should be a high index of suspicion for VIPoma in patients with chronic watery diarrhea and persistent hypokalemia. Reference: 1. Abu-Zaid, A., Azzam, A., Abudan, Z., Algouhi, A., Almana, H., Amin, T. Sporadic pancreatic vasoactive intestinal peptide-producing tumor (VIPoma) in a 47-year-old male. Hematol Oncol Stem Cell Ther. 2014; 7(3): 109-115.