Hyperammonemic encephalopathy: a rare presentation of fibrolamellar hepatocellular carcinoma.

Fibrolamellar carcinoma (FLC) is a rare malignant hepatocellular tumor of unknown etiology, arising almost exclusively from noninfected, noncirrhotic liver of young adults. FLC has traditionally been considered to have better survival than hepatocellular carcinoma; however, this notion might be highly erroneous. Patients with metastatic disease at presentation have a dismal prognosis with 5-year survival of only 15%. We describe a case of highly aggressive metastatic FLC that presented as hyperammonemic encephalopathy, which has never been previously reported in the literature.