Endocrine Abstracts

An 84 year old female with a known history of chronic kidney disease (stage IV) and benign lung tumour presented to the Emergency Department with collapse. She had suffered recurrent collapse over the previous 2 years. Of note she reported significant weight gain during this period. She was diagnosed with symptomatic hypoglycaemia (venous blood glucose 2.8 mmol/l). She was admitted to the ward and found to have recurrent hypoglycaemia both when fasting and post-prandial.

Investigations: Capillary blood glucose 2.5 mmol/L, venous glucose 3.2 mmol/L. Cortisol 413 nmol/L, insulin <1.0 mU/L, C-Peptide 122 pmol/l. IGF1 4.2 nmol/L, creatinine 296 umol/L. CXR: Large left lower lobe mass, consistent with known spindle cell lung fibroma. Given this, non-islet cell tumour hypoglycaemia was suspected and IGF2 levels were measured at 236.4 nmol/l. IGF2:IGF1 was 31.1, consistent with non-islet cell tumour hypoglycaemia.

Management: She was commenced empirically on prednisolone, and dose titrated down to the lowest effective dose. At 10 mg/day she suffered no hypoglycaemia. Given her disabling symptoms a multidisciplinary decision was taken to proceed with surgical resection of the tumour. She underwent a complete resection, and has made a good recovery functionally.

Follow-up: She reports no further hypoglycaemic events despite weaning for corticosteroid therapy. Histology confirmed a benign spindle cell lung fibroma. Repeat IGF2 measurement confirmed that secretion had ceased.

Discussion: Non-islet cell tumour hypoglycaemia is a rare entity, which has been described in other patients with pleural fibromas. It should be considered in patients with benign lung mass. Corticosteroid therapy is an effective means of symptom control, but surgery is curative.