[Use of a somatostatin analog to improve a patient's condition and the subsequent diagnosis of pancreatic VIPoma:a case report].

A 68-year-old woman with an 11-day history of sudden abdominal pain and severe watery diarrhea was transferred to our hospital due to an exacerbation of renal function despite hydration. After treatment for dehydration and acidemia was provided in our intensive care unit, patient's renal function improved. Contrast-enhanced abdominal computed tomography was finally performed, revealing a hypervascular pancreatic mass with multiple hepatic masses. This imaging finding along with her clinical symptoms indicated watery diarrhea hypokalemia achlorhydria (WDHA) syndrome caused by a pancreatic VIPoma. Somatostatin analog was administered immediately leading to the improvement of her diarrhea and her general condition. As a result, endoscopic ultrasonography-guided fine-needle aspiration could be performed. Consequently, she was diagnosed with a pancreatic neuroendocrine tumor. She then underwent surgical resection of the pancreatic tumor and liver metastasis. As revealed in the immunohistochemical analysis of the excised tumor tissue, VIP was highly expressed, resulting in the final diagnosis of pancreatic VIPoma. Therefore, the immediate use of a somatostatin analog is crucial for improving the patient's general condition and achieving a definitive diagnosis pathologically when a patient is suspected of having a pancreatic VIPoma.