DNAJB1-PRKACA-positive metastatic fibrolamellar carcinoma with unknown primary in a pediatric patient

Fibrolamellar carcinoma (FLC) is a rare variant of hepatocellular carcinoma, occurring in children and young adults without underlying liver disease. The diagnosis is based on morphological characteristics of the tumor, supplemented by immunohistochemistry and/or genetic testing. Recently, the presence of a characteristic DNAJB1-PRKACA fusion gene has been associated with FLC. Herein, we report a case of FLC presenting as peritoneal carcinomatosis in a 14-year-old female. Interestingly, no liver tumor was seen on imaging, and an alternative possibility is that the tumor arose outside the liver as a hepatoid carcinoma with fibrolamellar features.