Which findings on MRI are characteristic of fibrolamellar hepatocellular carcinoma?

Updated: Sep 05, 2019
  • Author: W Ross Stevens, MD; Chief Editor: John Karani, MBBS, FRCR  more...
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Answer

Fibrolamellar carcinoma is typically identified on MRI scans as a large, well-defined, lobulated mass. On T1-weighted images, the tumors tend to be mostly homogeneous and hypointense relative to the liver. A minority of tumors may be heterogeneous and isointense. On T2-weighted images, the tumors are commonly heterogeneous and, most often, hyperintense with respect to the liver. [21, 17] The images below demonstrate the hypointensity and hyperintensity of T1- and T2-weighted images of fibrolamellar carcinoma. [12, 10, 19]

T1-weighted magnetic resonance image of the liver T1-weighted magnetic resonance image of the liver in a patient with fibrolamellar carcinoma shows a lobulated and well-defined mass with a relatively homogeneous, hypointense appearance.
T2-weighted magnetic resonance image (same patient T2-weighted magnetic resonance image (same patient as in the previous image) shows a fibrolamellar carcinoma with increased signal intensity relative to that of the surrounding liver.

The central scar usually appears hypointense on all images obtained with all sequences. The appearance of the scar on MR images can be useful in differentiating fibrolamellar carcinomas from FNH, because scars in FNH tend to be hyperintense on T2-weighted images. Both fibrolamellar carcinoma and FNH are characterized primarily by generally subtle deviations of signal intensities on precontrast T1-weighted images and T2-weighted images, as compared to background liver parenchyma, arterial hyperenhancement, and the presence of a central scar. Imaging features that may favor fibrolamellar carcinoma over FNH on MRI include the greater heterogeneity of lesion texture of fibrolamellar carcinoma, the hypointensity of the central scar of fibrolamellar carcinoma on T2-weighted images, and portal venous hypoenhancement. [10, 18]

Fibrolamellar carcinomas typically do not contain intracellular fat; therefore, the presence of fat on fat-saturated, in-phase, and out-of-phase MRI scans suggests HCC or an adenoma. [19]

On gadolinium-enhanced magnetic resonance images, the enhancement patterns seen in fibrolamellar carcinomas are similar to those seen on contrast-enhanced CT scans. Early heterogeneous enhancement occurs during the arterial phase and progresses to more homogeneous enhancement during delayed phases. The central scar does not enhance during the arterial phase, but it may demonstrate mild enhancement in the later portal or equilibrium phases.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.


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