Poster Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Insulinoma: a rare cause of hypoglycaemia (#400)

Hui Yi Ng 1 , Veronica Wong 2 , Alexia Pape 1
  1. Endocrinology, Wollongong Hospital, Wollongong, NSW, Australia
  2. Endocrinology, Concord Repatriation General Hospital, Concord, NSW, Australia

We present a case of an 89 year old man who presented to hospital after a motor vehicle accident potentially caused by hypoglycaemia. He was not known to be diabetic. He was also found to have urinary sepsis and renal failure, which was thought to be contributing to the hypoglycaemia. Despite treatment and resolution of this, the hypoglycaemic episodes continued after short periods of fasting. He gave a history of at least 2 further episodes of possibly significant hypoglycaemia in the preceding year. During one episode, he had a documented finger prick blood glucose of 1.6 mmol/L on ambulance attendance, but this was not further investigated at the time.

Further evaluation in hospital showed evidence of endogenous hyperinsulinaemic hypoglycaemia;1 glucose 2.2 mmol/L (3-5.5 mmol/L), insulin 9.5 mU/L (2.6-24.9 mU/L), C-peptide 1.16 nmol/L (0.37 – 1.47 nmol/L) and pro-insulin 14.4 pmol/L (< 13.3 pmol/L). A CT scan showed an indistinct mass lesion at the tip of the pancreas, which was suspicious for a tumour on MRI. There was no evidence of hepatic metastases on imaging.

He underwent a laparascopic distal pancreatectomy, which showed a well-demarcated solitary lesion measuring 13x10x8mm in the distal tail of the pancreas. There was no lymphovascular or perineural invasion, and the Ki67 stain was <1%, suggesting a low-grade tumour.

Despite several post-operative complications he recovered well and has had no further episodes of hypoglycaemia.

Insulinoma is mostly benign, functioning neoplasm of the pancreas. It is a rare cause of hypoglycaemia. It has an incidence of 4 per million persons per year and does not have a predilection for any particular age group, ethinicity and gender.2

Diagnosis of this condition can be challenging; our case study will review the literature on the diagnosis, differential diagnosis of insulinoma and new therapeutic options for the treatment of insulinomas.

  1. Cryer PE, Axelrod L, Grossman AB, Heller SR, Montori VM, Seaquist ER, Service FJ. Evaluation and Management of Adult Hypoglycaemic Disorders: An Endocrine Society Clinical Practice Guidelines. J Clin Endocrinol Metab, March 2009, 94 (3):708-728
  2. Okabayashi T, Shima Ym Sumiyoshi T, Kozuki A, Ito S, Ogawa Y, Michiya K, Hanazaki K. Diagnosis and management insulinoma. World Journal of Gastroenterology 2013 February 14; 19(6):829-837.