Fibrolamellar hepatocellular carcinoma mimicking ornithine transcarbamylase deficiency.

We report an unusual case of recurrent non-hepatic hyperammonaemic encephalopathy in an adult patient. She had a previous history of treated fibrolamellar hepatocellular carcinoma (FLC). This posed a diagnostic challenge, as she had normal liver function tests and normal looking liver on imaging but with extra hepatic metastases. This case highlights the importance of measuring plasma ammonia levels in all patients presenting with unexplained acute confusion. Clinical awareness of non-hepatic hyperammonaemic encephalopathy can contribute to early diagnosis and timely initiation of life-saving treatment. Delay in treatment results in irreversible brain damage, deep coma and death. Treatment of hyperammonaemia must begin prior to confirmation of aetiology, for a favourable outcome. This case also highlights the need for further research to understand the exact mechanism of hyperammonaemia in hepatocellular carcinoma.