Metabolic effects of an insulin-like factor causing hypoglycaemia in a patient with a haemangiopericytoma

We have studied a patient with fasting hypoglycaemia and skin lesions (sign of Leser-Trélat) related to a retroperitoneal haemangiopericytoma in whom removal of the tumour resulted in immediate cure of hypoglycaemia. Before removal of the tumour, severe fasting hypoglycaemia was associated with undetectable insulin and C-peptide levels. She required 16.9 mumol/kg/min (10.4 g/h) of glucose intravenously to prevent hypoglycaemia and endogenous glucose production (measured using tritiated glucose) was suppressed to 1.3 mumol/kg/min while the whole-body glucose utilization rate was elevated at 18.2 mumol/kg/min. After removal of the tumour both endogenous glucose production rate and utilization rate returned to normal (11.5 mumol/kg/min). Resting energy expenditure, measured by indirect calorimetry, was markedly elevated at 2109 kcal/day (161% of predicted) and fell to 1205 (97% of predicted) after the tumour was removed. Glucose oxidation was also enhanced at 8.5 mumol/kg/min and fell to 3.3 mumol/kg/min after removal of the tumour. Other metabolites and hormones measured, and their response to oral glucose, were all consistent with the presence of a circulating substance with similar properties to insulin. We conclude that her hypoglycaemia resulted primarily from suppression of endogenous glucose production but also from enhanced glucose utilization. These effects were the result of a circulating growth factor sharing many metabolic effects with insulin, but with a much greater effect on resting energy expenditure and glucose oxidation.