Fibrolamellar Carcinoma

Fibrolamellar carcinoma (FLC) is a rare primary liver cancer that arises in a background of normal liver, most commonly in teenagers and young adults. FLC has been shown to be induced by a deletion of chromosome 19 that results in the formation of a fusion between the genes encoding the heat-shock protein DNAJB1 and the catalytic subunit of protein kinase A (PRKACA). Rarely, FLC occurs as a component of the Carney complex of neuroendocrine tumors and skin pigmentation due to mutations in the regulatory subunit of protein kinase A (PRKAR1A). Histologically, FLC is characterized by eosinophilic tumor cells with abundant cytoplasm and prominent nucleoli. The cytoplasm is filled with mitochondria and lysosomes. FLC frequently shows striking intratumoral fibrosis organized into typically parallel, or lamellar, bands. In FLC, ultrasound typically shows a mass of variable echogenicity. A hypoechoic central scar and small, focal calcifications may be seen. On multiphasic contrast-enhanced CT or MRI, most FLCs show heterogeneous arterial phase hyperenhancement with variable enhancement during portal venous and delayed phase imaging. FLCs are often homogenously hypointense on T1-weighted imaging, heterogeneously hyperintense on T2-weighted imaging, and hyperintense on DWI. FLCs often show metastases to perihilar, upper abdominal, and mediastinal lymph nodes. Treatment options for FLC include aggressive surgical resection and lymphadenectomy, image-guided percutaneous thermal ablation, locoregional therapies such as transarterial embolization, and systemic therapies.