Presentation
Epigastric pain
Patient Data
- ~8 cm mass centered in liver segment 4
- heterogeneous consistency, a combination of tissue isodense to normal liver parenchyma, lower-attenuating tissue, and smaller areas of bulk fat-attenuation
- overall round contour, although focal lobulations appear extend outward beyond margin of primary lesion
- extensive left hepatic bile duct dilatation, with metal transpapillary bile duct stent positioned for drainage of right hepatic ducts
- mild periportal edema
- vasculature
- middle hepatic vein non-opacified
- left portal vein branch is narrowed-but-patent
- accessory right hepatic artery arising from SMA
- non-specific mildly enlarged gastrohepatic and periportal lymph nodes
- pancreatic body/tail lipoma
- uncomplicated cholelithiasis
- ~8 cm mass centered in segment 4, causing extrinsic compression on left hepatic bile ducts, atrophy of left lateral section of liver
- heterogenous consistency
- central/left portion with arterial hyperenhancement
- central area with washout (hypoenhancement relative to liver parenchyma)
- right peripheral lobulated portion shows signal-loss on both opposed-phase
- possible 'pseudocapsule' appearance on postcontrast images (portal phase, axial & coronal)
- images and fat-suppressed images, indicating both intravoxel and macroscopic fat content
- mild extension into the adjacent liver segments (2, 3, 5, 8)
- heterogenous consistency
- right hepatic ducts drained via transpapillary biliary stent
- vasculature
- non-visualization of middle hepatic vein, distal left portal vein
- accessory right hepatic artery, arising from SMA
- pancreatic body/tail lipoma
- uncomplicated cholelithiasis
Representative image from CT-guided biopsy of segment 4 mass.
Surgical pathology
Liver, mass, core biopsy
- Well to moderately differentiated hepatocellular carcinoma
Case Discussion
The differential diagnosis for fat-containing lesion should include hepatocellular carcinoma. Indeed, "excess fat within a mass, in whole or in part, relative to adjacent liver" suggests hepatocellular origin and may represent an ancillary feature of HCC according to LI-RADS.
As HCC develops, a typical pattern of hepatocarcinogenesis includes intralesional fat accumulation in early disease, which often decreases in later disease due to transformation into malignant tissue. One exception to this pattern is so-called "steatohepatitic HCC", which exhibits progressive fat accumulation as disease progresses.
One of the interesting aspects of this case is that there are no overt morphologic findings of cirrhosis by imaging.
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