Severe hypoglycaemia caused by raised insulin-like growth factor II in disseminated breast cancer

A 60 year old woman with disseminated ductal carcinoma of the breast developed non-islet cell tumour induced hypoglycaemia (NICTH). The concentrations of the two insulin-like growth factors, IGF-I and IGF-II, were < 2 nmol/l and 94.1 nmol/l, respectively. The IGF-II to IGF-I ratio was > 47 (normal < 10). Insulin (< 3 mu/l) and C peptide (< 100 pmol/l) were both undetectable.