Hepatic hemangioma
Updates to Article Attributes
Hepatic haemangiomas, also known as hepatic venous malformations, are benign non-neoplastic hypervascular liver lesions. They are frequently diagnosed as an incidental finding on imaging, and most patients are asymptomatic. From a radiologic perspective, it is important to differentiate haemangiomas from hepatic neoplasms.
Terminology
It is important to note that according to newer nomenclature (ISSVA classification of vascular anomalies) these lesions are merely known as slow flow venous malformations. Having said that, it is probably helpful in reports to retain the word haemangioma, as this term is ubiquitous in the literature and familiar to most clinicians. The remainder of this article uses the term 'hepatic haemangioma' for consistency with the majority of the existing literature.
Cavernous venous malformations are found throughout the body. This article focuses on hepatic cavernous haemangiomas. For a general discussion, please refer to the general article on cavernous venous malformation.
Epidemiology
Hepatic haemangiomas are much more common in females, with a F:M of up to 5:1 17.
Pathology
Hepatic haemangiomas are thought to be congenital in origin, non-neoplastic, and are almost always of the cavernous subtype. Blood supply is predominantly hepatic arterial, similar to other liver tumours. A peripheral location within the liver is most common 3.
Sub types
- typical hepatic haemangioma
- atypical hepatic haemangioma 9
- giant hepatic haemangioma
- flash filling hepatic haemangioma: can account for up to 16% of all hepatic haemangiomas
- slow fill hepatic haemangioma: can account for around 8-16% of all haemangiomas 12
- calcified hepatic haemangioma
- hyalinised/sclerosed hepatic haemangioma
- other unusual imaging patterns
The presence of a few hepatic haemangiomas in the liver is not uncommon, but rarely a large number hepatic haemangiomas may occur (see hepatic haemangiomatosis).
Associations
- extra hepatic haemangiomata
- hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu disease)
- Kasabach-Merritt syndrome: with giant haemangiomas
- hepatic arterio-portal shunts
Radiographic features
Ultrasound
- typically well-defined hyperechoic lesions
- a small proportion (10%) are hypoechoic, which may be due to a background of hepatic steatosis, where liver parenchyma itself is of increased echogenicity
- colour Doppler: may show peripheral feeding vessels
-
contrast-enhanced ultrasound
- arterial phase: peripheral nodular discontinuous enhancement
- portal venous and delayed phases: continued "filling in" of the lesion, until the entire hemangioma is hyperechoic relative to background liver
See hyperechoic liver lesions for a further differential.
CT
Most haemangiomas are relatively well defined. The dynamic enhancement pattern is related to the size of its vascular space 1. Features of typical lesions include:
- noncontrast: often hypoattenuating relative to liver parenchyma
- arterial phase: typically show discontinuous, nodular, peripheral enhancement (small lesions may show uniform enhancement)
- portal venous phase: progressive peripheral enhancement with more centripetal fill-in
- delayed phase: further irregular fill-in and therefore iso- or hyper-attenuating to liver parenchyma
Other described features include:
MRI
Typical features include:
- T1: hypointense relative to liver parenchyma
- T2: hyperintense relative to liver parenchyma, but less than the intensity of CSF or of a hepatic cyst
-
T1 C + (Gd): often shows peripheral nodular discontinuous enhancement which progresses centripetally (inward) on delayed images
- haemangiomas tend to retain contrast on delayed (>5 minutes) contrast-enhanced images
- atypical haemangiomas may demonstrate slightly altered enhancement patterns
-
T1 C + (hepatobiliary contrast, Eovist)
- in general, delayed imaging with Eovist/Gd-BOPTA may not be helpful since haemangiomas can have a variable appearance that ranges from hypointensity to diffuse and central enhancement
-
DWI: hyperintense on diffusion-weighted imaging (DWI) even with high b-values due to slow blood flow and
aremay be hyperintense or mixed (hyper and hypointense regions) on ADC mapindicatingrestricted diffusion
Nuclear medicine
SPECT
99Tc RBC labelled SPECT can be sensitive for larger lesionsand typically demonstrate decreased activity on initial dynamic images followed by increased activity on delayed, blood pool images.
Treatment and prognosis
They are benign lesions. Recommendations for patients with no known risk factors for hepatic malignancy can range from centre to centre from performing confirmatory examinations (MR imaging, triphasic CT or scintigraphy) to considering follow-up ultrasound in 6 months to confirm stability, to performing no further imaging evaluation 13. Some authors propose surgical resection for patients with progressive abdominal pain in combination with size greater than 5 cm 14.
Differential diagnosis
The diagnosis of haemangioma can usually be made with high specificity if the imaging characteristics are typical. General imaging differential considerations for a haemangioma depend on the imaging modality and the patient's history, but may include:
-
hepatic metastases
- hypervascular hepatic metastases show marked early enhancement with a continuous ring that on later images fills in centrally and progressive centripetal fill-in may occur on delayed phases 11
- hepatocellular carcinoma
-
hepatic cyst
- small lesions (generally less than 1 cm) on CT may be equivocal and can be clarified with a targeted ultrasound examination
- hepatic abscess
- regenerative nodules / dysplastic nodules
- cystic hepatic or biliary neoplasm
- haemangioendothelioma
-</ul><p>Other described features include:</p><ul><li><a href="/articles/bright-dot-sign-atypical-liver-haemangioma">bright dot sign</a></li></ul><h5>MRI</h5><p>Typical features include:</p><ul>- +</ul><p>Other described features include:</p><ul><li><a href="/articles/bright-dot-sign-atypical-liver-haemangioma-1">bright dot sign</a></li></ul><h5>MRI</h5><p>Typical features include:</p><ul>
-<strong>DWI:</strong> hyperintense on <a href="/articles/diffusion-weighted-imaging-1">diffusion-weighted imaging</a> (DWI) even with high b-values due to slow blood flow and are hypointense on ADC map indicating <a href="/articles/restricted-diffusion">restricted diffusion</a> <sup>16</sup>- +<strong>DWI:</strong> hyperintense on <a href="/articles/diffusion-weighted-imaging-1">diffusion-weighted imaging</a> (DWI) even with high b-values due to slow blood flow and may be hyperintense or mixed (hyper and hypointense regions) on ADC map <sup>16</sup>
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