Centrifugal (inside-out) enhancement of liver hemangioma are a type of atypical hepatic hemangioma, which due to its imaging features, often raises the concern of a malignant process rather than a benign one.
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Epidemiology
Centrifugal (inside-out) enhancement of liver hemangiomas are a relatively uncommon entity.
Pathology
Being a subtype of hepatic hemangioma, it is also composed of dilated endothelial lined vascular channels and fibrous stroma.
Ultrasound
On ultrasound, most are hyperechoic - same as the typical hemangiomas.
Contrast-enhanced ultrasound
During contrast enhanced ultrasounds these lesions show the presence of an “inside-out” contrast-enhancement pattern, defined as the presence of central enhancing foci in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases.
CT
This lesion shows a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement is incomplete at contrast-enhanced scans.
MRI
T1: hypointense
T2: markedly hyperintense
C+ (Gd): gradual centrifugal enhancement
Other general features
Regardless of the precise histological composition and/or the exact mechanism that determine the appearance of centrifugal (inside-out) contrast-enhancement pattern of liver hemangiomas, radiologist should be aware that filling of hemangiomas is variable and not always in a classical concentric centripetal way.
CT and/or MRI may provide useful clues to the right diagnosis of this uncommon and atypical presentation of the most frequently encountered benign liver tumor
Differential diagnosis
Due to the atypical feature delayed enhancement, these lesions have to be differentiated from: