Flash filling hepatic hemangioma

Flash filling hepatic hemangiomas, also known as flash filling hepatic venous malformations, 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.

Terminology

It is important to note that according to newer nomenclature (ISSVA classification of vascular anomalies) these lesions are known as venous malformations . Having said that it is probably helpful in reports to include the word 'hemangioma' as this term is ubiquitous in the literature and most familiar to many clinicians. The remainder of this article uses the terms 'flash filling hemangioma' and 'flash filling hepatic venous malformation' interchangeably.

Epidemiology

They may account for 16% of all hepatic hemangiomas .

Pathology

Being a subtype of hepatic hemangioma, it is also composed of dilated endothelial lined vascular channels and fibrous stroma.

Radiographic features

Most are small in size (<2 cm).

Ultrasound

On ultrasound, most are hyperechoic - same as the typical hemangiomas.

CEUS

During CEUS these lesions show rapid, homogeneous hyperenhancement followed by hyper/isoenhancement relative to the adjacent liver due to the retention of contrast until the late phase without washout .

CT

On CT, these lesions are normally iso- to hypo-dense on unenhanced scans. There is a quick, brilliant and homogeneous enhancement of the lesion in the arterial phase itself, hence the name "flash filling". In the rest of the phases, it retains the contrast and remains isodense to the adjacent vascular pool.

MRI
  • T1: hypointense 
  • T2: markedly hyperintense
  • C+ (Gd): prompt enhancement but no washout
Other general features

At times the venous matrix of these hemangiomas may develop phleboliths, which when recognized should be promptly associated with hemangioma.

Differential diagnosis

Due to the atypical feature of quick, brilliant arterial phase enhancement, these lesions have to be differentiated from:

See also

Siehe auch: