Pancreatic Neuroendocrine Tumor-Induced Hyperammonemic Encephalopathy in the Absence of Hepatic Involvement

Hyperammonemic Encephalopathy in a Patient with Pancreatic Neuroendocrine Tumor and Portosystemic Shunt

Hyperammonemia can lead to encephalopathy and may be accompanied by a diagnostic dilemma. Imaging as well as biochemical analyses are the cornerstone for identifying possible underlying causes such as severe liver disease or urea cycle defect. We report a case of a patient that presented with neurological deficits based on hyperammonemia in the presence of a large pancreatic neuroendocrine tumor (PNET) and portosystemic shunts in the liver. Prior cases are rather scarce, and the exact mechanism is not fully understood. The case illustrates the added value of a multimodality imaging approach in patients presenting with hyperammonemia-induced encephalopathy.

Marked improvement in hyperammonaemic encephalopathy from multimodal treatment of metastatic neuroendocrine tumour

Gastroenteropancreatic neuroendocrine tumours (GEPNETs) are a heterogenous group of tumours which are rising in incidence. Morbidity and mortality related to these tumours is dependent on the location of metastatic spread. Hyperammonaemia and subsequent encephalopathy has previously been described in GEPNET and is typically associated with a poor prognosis. We describe a case of a 55-year-old woman with hyperammonaemic encephalopathy and a new diagnosis of GEPNET. Given the poor prognosis and the outcomes in this patient group we feel this case highlights the benefit of a multimodality treatment approach including peptide receptor radionucleotide therapy and transarterial chemoembolisation.