Endocrine Abstracts

Background: Metastatic insulinomas are very rare (fewer than 1:100000) and therefore may pose a therapeutic challenge as there are no case controlled studies comparing the efficacy of various therapeutic approaches avialable. The Ki 67 index from the histology of the primary tumour is an established prognostic marker for metastatic disease with tumours showing low Ki 67(<3%) being defined as low risk of early recurrence.

Case Presentation: A 60 year old female presented with severe episodes of fasting hypoglycaemia with glucose levels as low as1 mmol/l requiring prolonged dextrose 10% infusion. This was accompanied by raised insulin and C-peptide values when confirmed severe hypoglycaemia occured (>100 mU/l and 2953 pmol/l, respectively). Her past medical history included a distal pancreatectomy and splenectomy fourteen years ago when she had an incidental finding of a cystic lesion in the pancreas. The histology at the time revealedit was a low grade pancreatic neuroendocrine tumour (NET). For the next 5 years she was having regular follow ups with repeat imaging of her abdomen and repeat chromogranin A and B levels and as there was no evidence of tumour recurrence hence she was discharged from the surgical follow up. Repeat CT imaging revealed multiple large volume liver metastases (largest measuring 11.3 cm), an 8.2 cm left para-aortic metastatic tumour deposit anda smaller metastatic deposit anterior to the left renal vein. CT guided biopsy showed a grade 2 well differentiated NET with Ki 67 4.5%. Despite commencementand uptitration of diazoxide (100 mg TDS) and octreotide (200 mg TDS), patient continued to have symptomatic severe hypoglycaemic episodes requiring continous 10% dextrose infusion at 125 mls/hour. She also developed drug-induced rash. Following a multidisciplinary team discussion, decision wasmade to perform hepatic artery embolisation but despite that the hypoglycaemic episodes recurred the next day. Eventually, patient under went laparatomy for right hemihepatectomy and resection of the left retroperitoneal mass. She was euglycaemic after the procedure and had a good postoperative recovery. Subsequent histology showed well differentiated grade 2 NETconsistent with metastatic spread of previous pancreatic neuroendocrine tumour (insulinoma). She remains euglycaemic and well.

Discussion: This case illustrated that metastases from a neuroendocrine tumour may occur many years since initial presentation. Metastatic insulinoma may be quite challenging to manage. The initial approach is to manage symptoms pharmacologically whilst decision is made regarding definite management with options including surgery, embolization, radiotherapy, chemotherapy or liver transplant depending on individual circumstances.