Endocrine Abstracts

Neuroendocrine tumours are slow growing and could be mistaken for other more malignant tumours with poorer prognosis. Their secretory profile may alter with time. The importance of awareness of these tumours and their clinical behaviour is illustrated by the case of a 78-year-old woman who presented with recurrent fasting hypoglycaemia.

The patient had been diagnosed with metastatic pancreatic adenocarcinoma a year previously on the basis of radiographic appearances. In the weeks prior to admission, she had been admitted several times to different hospitals with severe hypoglycaemia, when her partner had been unable to wake her from sleep.

Elevated insulin (197 pmol/l) and C-peptide (1147 pmol/l) levels were demonstrated during an episode of hypoglycaemia (glucose 2.1 mmol/l). Fasting gut hormone profile showed elevated levels of pancreatic polypeptide, and chromogranin A and B. Repeat CT abdomen showed little progression of the primary tumour or metastases. Symptomatic control proved challenging, with a combination of dietary advice, diazoxide (200 mg daily) and prednisolone (40 mg daily) proving ineffective. Radio-labelled octreotide scanning showed uptake on both primary tumour and metastases. Subcutaneous octreotide was, therefore, added resulting in control of hypoglycaemia. Chemotherapeutic options were discussed but declined. Unfortunately, she died a few weeks later of pneumonia.

Classically, insulinomas present with recurrent hypoglycaemia and the primary tumour is then sought. Surgical excision of the tumour is the most effective treatment for hypoglycaemia; if this is not possible, diazoxide may be administered to inhibit insulin secretion. This case is unusual in that the diagnosis of metastatic pancreatic tumour predated the presentation with recurrent hypoglycaemia by one year. This may have been due to a combination of the tumour altering its secretory profile and hypoglycaemia unawareness. Symptomatic control can be difficult in patients who are not suitable for surgical cure and a combination of treatments may be necessary.