Endocrine Abstracts

Section 1: Case History: A 45-year-old gentleman attended the emergency department in December 2016 with an episode of stupor, confusion and lethargy with blood glucose of 1.8 mmol/l. He recovered after administration of IV glucose. He had ’funny spells’ for a year prior to the event. He had a history of childhood asthma and was not on any regular medications. There were no significant findings in the clinical examination and no relevant family history.

Section 2: Investigations: A 72 hour fasting test was arranging. After 3 hours, the patient developed symptoms of hypoglycemia. Serum glucose levels from this time were 2.8 mmol/l, Insulin 25.4pmol/l and C-peptide 3.25 nmol/l, suggestive of hyperinsulinemia hypoglycemia. The sulphonylurea screening was negative. The urea and electrolytes, thyroid, pituitary, adrenal and fasting gut hormone levels were within normal limits. His HbA1C was 28 (26-41 mmol/mol). An MRI of pancreas demonstrated that there was a 3.5 cm x 2.6 cm exophytic lesion arising from the tail of the pancreas, with some local lymphadenopathy.

Section 3: Results and treatment: The patient was managed well with dietary adjustment and glucose tablets. He was referred to Hepatobiliary MDT and had Gallium Dotate PET CT revealed that there was an uptake with the tail of pancreatic lesion without evidence of metastases. Subsequently, he successfully underwent Laparoscopic resection of a distal pancreatic insulinoma in June 2017. Histology showed a well differentiated grade 1 neuroendocrine tumour with an MiB1 of 1% pT2N0. The biochemical and genetic MEN1 screening was negative. There were no further hypoglycemic episodes until April 2021 where he had a hypoglycemic episode (Blood glucose 1.1 mmol/l) requiring an ambulance assistance. The paired serum glucose 2.9 mmol/l, Insulin 385pmol/l, proinsulin 535pmol/ and C-peptide 349pmol/l were suggestive of recurrent insulinoma. No new enhancing pancreatic lesion in repeated MRI pancreas was identified. The repeated fasting gut hormones were within normal limits. A HbA1C was 26 mmol/mol. He had been referred to Hepatobiliary MDT due to concern of recurrent insulinoma.

Section 4: Conclusions and points of discussions: This is a rare case of insulinoma. The risk of recurrence was 5 to 7 percent without MEN1 and occurred between 4 to 18.5 years after initial operation. There is a likelihood of risk of recurrence in this case clinically and biochemically. Therefore, the further repeating MRI pancreas, EUS to look for residual tissue and a 72 hours fasting test is indicated.