[Insulin-like growth factor-II secreting prostate tumour causing severe hypoglycaemi]

The authors present a case of an 82-year-old male patient who presented with frequent hypoglycaemia. Four years prior to the current evaluation the patient had been diagnosed with prostate carcinoma; however, he refused surgical treatment. Initial diagnostic tests indicated organic hypoglycaemia with low serum insulin levels. Insulinoma was excluded and further laboratory tests showed reduced serum insulin-like growth factor-II and normal serum chromogranin A levels as well as normal hypophysis and peripheral hormone values. The authors hypothesised that the severe hypoglycaemia might be the consequence of synthesis and secretion of insulin-like growth factor-II (or its prohormone) by the previously diagnosed prostate tumour. Insulin-like growth factor-II and its prohormone directly increases glucose uptake of the tumour, muscle and adipose tissue, decreases glucose release from the liver and downregulates insulin synthesis due to inhibition of the pancreatic beta cells. The patient required continuous intravenous glucose substitution initially with 5%, subsequently with 20% glucose infusion. Administration of other agents resulted only in temporary improvement. Prostatectomy was again considered but then excluded because of the recurrent hypoglycaemia and the poor general condition of the patient. Hypoglycaemia was finally controlled with glucose and diazoxide therapy, but no improvement in the general condition of the patients was observed and the patient deceased. Immunohistochemistry of the prostate sections showed a carcinoma with strong insulin-like growth factor-II staining, suggesting that insulin-like growth factor-II-secreting prostate tumour caused the severe hypoglycaemia.