Malignant insulinoma with extensive liver metastases presenting as disturbance of consciousness

A 56-year-old man was referred to our hospital for evaluation of episodic disturbance of consciousness. Hypoglycemic symptoms were noted and Whipple's triad was satisfied. The 75 g OGTT and the glucagon test revealed a high baseline insulin level and hyperreactivity to glucagon. A pancreatic tumor and liver metastases were found by abdominal computed tomography (CT). Based on the finding of liver biopsy, the final diagnosis was malignant insulinoma with liver metastasis. He selected conservative treatment and no hypoglycemic crisis has occurred for one year since discharge. Early diagnosis and long-term follow-up is necessary since this tumor is slow growing.