Endocrine Abstracts

A 54-year-old gentleman presented to his GP in July 2019 with significant weight loss, polyuria and nocturia for two to three months. His HbA1c was 78 mmol/mol. He was diagnosed with diabetes and started on Metformin 500 mg BD. Upon consultant review in September 2019, he reported a 26 kg weight loss over the preceding four years, much of which was apparently intentional, and right abdominal discomfort. His paternal grandmother died of pancreatic cancer, as did his paternal aunt. His maternal grandfather had diabetes and maternal grandmother had rheumatoid arthritis. He smoked 20 cigarettes per day for thirty years and drank alcohol in moderation. His systemic examination was unremarkable. There was no significant skin rash and urine ketones were negative. Full blood count, liver function tests and electrolytes were within normal limits. The possibility of type 1 diabetes was considered in view of his initial presentation, but, GAD and IA2 antibodies were negative. Given the weight loss and family history, CA 19–9 and MRI pancreas were requested. The CA 19–9 was normal and MRI pancreas and subsequent CT chest, abdomen and pelvis revealed a 5 cm pancreatic body tumour and multiple bi-lobar liver metastases. One of the hepatic lesions was biopsied and histology reported a well differentiated neuroendocrine tumour, with Ki67 highlights up to 5% of tumour nuclei. Immunohistochemistry revealed strong positivity with cytokeratin, synaptophysin and CD56. CK7, CK20 and chromogranin were negative. Octreotide scan demonstrated avidity in the pancreatic body primarily and bi-lobar liver metastases. There was no uptake in other areas. Ga68 DOTATATE PET confirmed the diagnosis by showing high uptake in body of pancreas and liver metastases (somatostatin 2 receptor positive). His PTH and calcium level were normal, likely excluding MEN1. His fasting glucagon level was 73 pmol/l (0–50) and chromogranin A was 151 pmol/l (0–60). Chromogranin B was > 250 pmol/l (0–150). Vasoactive intestinal peptide, pancreatic polypeptide, gastrin and somatostatin were normal. Somatostatin analogues were initiated as first-line therapy.

In conclusion, this case highlights the importance of careful consideration of the differential diagnosis when patients present with new-onset diabetes and atypical features, and awareness of neuroendocrine tumours (NET) of the pancreas as a cause.