Purpose: Vasoactive intestinal peptide (VIP) secreting tumor (VIPoma) constitutes a rare functional neuroendocrine tumor that most often originates from pancreatic islet cells and presents as a sporadic, solitary neoplasm of the pancreas. The purpose of this study was to systematically review the literature of pancreatic VIPomas and report clinicopathologic data and treatment modalities for this rare entity.
Methods: A systematic literature search was performed. The reviewed clinical series and case reports were included if they reported surgical treatment and also analyzed oncological outcomes on individual patients. Data extraction was performed using a standard registry pro-forma.
Results: The search resulted in 53 case reports and 2 case series including 65 patients in total. Median age reported was 54 years. The predominant pancreatic location was the pancreatic tail. The most common clinical symptom was watery diarrhea. Serum VIP levels were remarkably elevated in all patients. Distal pancreatectomy with or without splenectomy was the most commonly applied surgical procedure. Overall survival associated with pancreatic VIPoma was 67.7%, recurrence rate 40.4% and relevant median disease-free interval was 16 months.
Conclusions: VIPomas are functional tumors that secrete excessive amounts of VIP. Clinically, production of VIP causes refractory watery diarrhea, hypokalemia and achlorydria. As far as diagnosis is concerned, elevated VIP plasma levels are required. Moreover, the majority of VIPomas are malignant or have already metastasized on diagnosis. Despite recent research on the therapeutic strategies against pancreatic VIPoma, surgical resection appears as the only potentially curative approach.