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Definition:
Common benign tumor consisting of vascular channels lined by endothelial cells.
LI-RADS Categorization:
- Observations thought to definitely represent hemangiomas (HG) should be categorized LR-1.
- Observations thought to probably represent hemangiomas should be categorized LR-2.
- Observations that are indeterminate for hemangiomas versus HCC should be categorized LR-3 or LR-4.
Characteristic imaging features:
- Hemangiomas in patients with mild or early cirrhosis may have typical imaging features:
- Peripheral discontinuous nodule-like expanding enhancement or rapid enhancement that in its intensity parallels blood pool enhancement.
- Sharply circumscribed
- Round, oval, or lobulated
- Unenhanced CT
- Unenhanced MRI
- T1 hypointense
- T2 markedly hyperintense
- DW hyperintense (due at least in part to T2 shine-through)
Potential pitfalls and challenges:
- With progressive cirrhosis, hemangiomas tend to become smaller and more fibrotic (sclerotic), and as a result they may not have the classic diagnostic appearance often seen in the non-cirrhotic liver. Instead, they may have the following features:
- Involution and diameter reduction over time
- Retraction of overlying liver surface
- Rim-like enhancement
- Small puddles with slow or incomplete filling
- Enhancement less than that of blood pool
- Ill-defined rather than sharply circumscribed and distinctly lobulated
- T2w MRI:
- Mild-moderate rather than marked T2 hyperintensity
- Heterogeneous T2 hyperintensity corresponding to areas of variable intra-lesional fibrosis
- Radiologists should be aware that in patients with advanced cirrhosis hemangiomas may be difficult to diagnose confidently at CT and MRI. Comparison to prior studies when cirrhosis was less advanced may be helpful, as the hemangioma may have had more characteristic features previously. Another important diagnostic clue is diameter stability or diameter reduction over time.
Comments:
- Hemangiomas are seen less frequently in the cirrhotic than in the non-cirrhotic liver.
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