[Mesenchymatous tumour of the thigh causing hypoglycaemia with circulating protein of high insulin activity (author's transl)].

An 87-year-old woman underwent surgery for a dermato-fibrosarcoma of the thigh, responsible for hypoglycaemic episodes. There was a high level of NSILP contrasting with a low level of NSILAs. This is the second case where such a finding has been made in a patient suffering from an extra-pancreatic tumour causing hypoglycaemia. The possible aetiological role of NSILP in extra-pancreatic tumours causing hypoglycaemia is discussed.