Malignant insulinoma which expressed a unique creatine kinase isoenzyme: clinical value of arterial embolization as a palliative therapy.

A 76-year-old man with hypoglycemic coma was diagnosed as malignant insulinoma with multiple hepatic metastases. Embolization was done for two-thirds of the hepatic mass and it rapidly lowered the serum immunoreactive insulin. He was discharged without medication and has been free from hypoglycemia. After the embolization, the serum creatine kinase (CK) level increased transiently although there was no evidence of myocardial infarction. On electrophoresis, the CK activity showed an abnormal peak, suggesting mitochondrial CK. CK release after embolization has been reported in only a few cases with endocrine tumors, which might indicate some relationship between active energy metabolism and mitochondrial CK.