45 year old female with hypokalemic rhabdomyolysis due to VIP-producing composite pheochromocytoma

Background: Watery diarrhea, hypokalemia and achlorhydria (WHDA) syndrome due to vasoactive intestinal polypeptide (VIP)-producing extra-pancreatic tumors is rare.

Case presentation: We report on a 45-year-old woman who suffered from persistent secretory diarrhea over the last six years and who was admitted to hospital with complaints of muscular weakness and myalgia. Biochemical testing revealed pronounced rhabdomyolysis due to severe hypokalemia. Gastrointestinal evaluation of longstanding diarrhea including endoscopy of the upper and lower gastrointestinal tract and the small intestine did not show any pathologies. An abdominal computed tomography scan revealed a mass of 4×5cm in the left adrenal gland demonstrating a strong uptake in the (¹²³I)-labeled metaiodobenzylguanidine scintigraphy. Plasma levels of chromogranin A, calcitonin, parathormone, basal renin and most prominently VIP were increased in line with a increased 24h urinary secretion of noradrenaline, dopamine, normetanephrine and vanillymandelic acid. A WDHA (watery diarrhea, hypokalaemia, achlorhydria) syndrome with hypokalemic rhabdomyolysis due to a VIP-producing left adrenal tumor was diagnosed. The adrenal tumor was removed surgically that showed histologically a pheochromocytoma and a glanglioneuroma component. Diarrhea stopped immediately after surgery together with a normalization of laboratory parameters.

Conclusions: This case report focuses on the rare clinical presentation of secretory diarrhea and electrolyte disturbances in combination with hypokalemic rhabdomyolysis which was caused by a VIP-producing composite pheochromocytoma.