Endocrine Abstracts

High grade pancreatic NETs are usually non-functional. Here, we report a case of a patient with a high grade pancreatic NET, which was initially non-functional but became functional after chemotherapy. He was initiated on a flash glucose monitoring device (FreeStyle Libre®) avoiding the need for frequent capillary blood glucose monitoring. Using this novel approach, we demonstrated an improvement in his disabling hypoglycaemia with medical treatment. A 45-year-old professional athlete presented with abdominal pain and an urgent CT scan of the abdomen revealed a 4 cm tumour in the tail of the pancreas with multiple liver metastases. A liver biopsy confirmed a high-grade but differentiated tumour with a Ki67 index of 30–40% (G3). The patient was referred for chemotherapy (carboplatin/etoposide). During one hospital admission after chemotherapy, he was incidentally found to have hypoglycaemia (2.6 mmol/L) with an inappropriately normal insulin level of 61.0 pmol/L (reference range 17.8–173), along with a C peptide level of 1465 pmol/L (reference range 370–1470), and highly elevated proinsulin levels of 870 pmol/L (reference range 0–10). He initially required a continuous intravenous dextrose infusion to maintain euglycaemia and this was weaned slowly as he was simultaneously commenced on oral dexamethasone and diazoxide and later on a somatostatin analogue (lanreotide) with significant improvement of hypoglycaemia. He was discharged home with a Free Style Libre^®. Periodic clinical follow-up and data download of his blood glucose profile demonstrated a significant improvement in hypoglycaemia. Interestingly, our patient did not report symptoms of hypoglycaemia at diagnosis but clearly developed hypoglycaemia later on. We hypothesize that initial chemotherapy, in this case, may have preferentially targeted high-grade tumour cells allowing for an expansion of low-grade cells that potentially contributed to the observed hyperinsulinaemia and functionality. To our knowledge, this phenomenon has never been reported before. Further, we have shown that a flash glucose monitoring normally reserved for patients with type 1 diabetes has clinical utility in the management of hypoglycaemia in the context of a neuroendocrine tumour.