A 75-year old gentleman presented with symptoms of increasing lethargy, loss of appetite associated with weight loss and constant micturition. A CT scan showed extensive peritoneal mass in the lower abdomen and pelvis with disseminated intraperitoneal malignancy. A CT guided biopsy confirmed a poorly differentiated tumour. Immunohistochemistry showed that all the cytokeratin markers were negative, but vimentin was positive and CD117 (c-kit) was strongly positive, indicating that it was a malignant GIST. In the following two weeks, the patient experienced recurrent episodes of blackouts associated with excessive sweating and was admitted to hospital. The patient showed a suboptimal response to short synacthen test. Blood tests during an episode of spontaneous hypoglycaemia revealed.
|Blood glucose||1.4 mmol/L||46.4|
|Cortisol||248 nmol/L||Reduced response to a glucose of 1.4 mmol/L|
|Growth hormone||4.6 mu/L||05|
|IGF I||2.9 nmol/L||636|
|IGF II:IGF I ratio||21.3||<10|
While on the ward, he had recurrent episodes of spontaneous hypoglycaemia requiring correction with 10% dextrose infusion. There was no improvement in blood sugars despite treatment with hydrocortisone and octreotide. As an elevated IGF II:IGF I ratio confirmed the diagnosis of non-islet cell hypoglycaemia, the patient was commenced on Growth hormone 0.02 mg/kg subcutaneously daily with successful stabilization of blood sugars.