Pancreatic neuroendocrine microadenomatosis presenting as a functional VIPoma

Pancreatic microadenomas are benign tumors of neuroendocrine origin less than 5 mm in size. Whereas most microadenomas are non-functional; a few rare functional pancreatic microadenomas have been described in the setting of multiple endocrine neoplasia type one (MEN-1). In this report, we describe a unique case of multiple functional microadenomas of the pancreatic head in a patient who presented with persistent secretory diarrhea, refractory hypokalemia, metabolic acidosis and elevated plasma vasoactive intestinal peptide (VIP) levels. Following extensive serologic, radiographic and endoscopic work up, our patient underwent open pancreaticoduodenectomy with subsequent resolution of diarrheal symptoms and electrolyte abnormalities on postoperative follow up.