Oxalate nephropathy from untreated pancreatic insufficiency in a neuroendocrine tumour patient.

Pancreatic exocrine insufficiency (PEI) is an under-recognised cause of chronic diarrhoea in patients with neuroendocrine tumours (NETs). If left untreated or undertreated, PEI can lead to complications such as oxalate nephropathy (ON), which may result in loss of kidney function and potentially limit oncologic treatment options, including peptide receptor radionuclide therapy (PRRT). We present a man in his late 60s with a small bowel NET who developed persistent, uncontrolled diarrhoea for several years. The diarrhoea was attributed to multiple factors, including secretory NET (ie, carcinoid syndrome), bile acid diarrhoea and PEI secondary to somatostatin analogue therapy. Due to financial constraints, the patient was unable to consistently take pancreatic enzyme replacement therapy (PERT). Years after the diagnosis of NET, the patient developed a new onset worsening of kidney function. Further work-up, including a kidney biopsy, confirmed ON, which significantly limited subsequent treatment options, including PRRT. Routine screening for PEI and early initiation of PERT should be considered in all NET patients with chronic diarrhoea to prevent ON and preserve future treatment options.