giant hepatic haemangioma
Giant hepatic hemangiomas, also known as giant hepatic venous malformations, are relatively uncommon non-neoplastic vascular lesions of the liver, which can be strikingly large and mimic tumors.
It is important to note that according to newer nomenclature, these lesions are known as venous malformations (ISSVA classification of vascular anomalies) . Having said that, it is probably helpful to include the word 'hemangioma' in reports, as this term is ubiquitous in the literature and more familiar to many clinicians. The remainder of this article uses the terms 'giant hepatic hemangioma' and 'giant hepatic venous malformation' interchangeably.
In addition, there is poor agreement in the literature as to the exact definition of what constitutes a "giant" hepatic hemangioma, as some of the literature defines as a size >4 cm but others >6 cm or even >10 cm. Either way, they are examples of atypical hepatic hemangiomas .
Many are asymptomatic; however, hemorrhage, thrombosis, and mass effect may lead to abdominal fullness and pain. Depending on location and size, mass effect on adjacent structures (biliary tree or vascular structures) may also lead to specific clinical presentations.
Hemorrhage and/or rupture may also be encountered (typically following trauma or biopsy).
Giant hepatic venous malformations may contain areas of central necrosis/liquefaction, hemorrhage, peripheral calcification, fibrosis, and thrombosis, resulting in heterogeneous appearance and incomplete enhancement, even on very delayed imaging.
Giant hemangiomas may demonstrate similar findings to their smaller relatives, although findings are less consistent.
On non-contrast scans, the lesions are usually heterogeneously hypoattenuating masses with marked central areas of low attenuation.
The typical enhancement pattern is peripheral nodular discontinuous enhancement that gradually fills centrally and follows aortic attenuation (same as for smaller hemangiomas).
Contrast filling may be slow and the central portions may never demonstrate complete contrast fill in. Occasionally, they may exhibit minimal contrast enhancement.
Capsular retraction from scarring may also be seen.
- sharply marginated, hypointense mass
- cleft-like areas of low signal intensity
- T1 C+ (Gd)
- cleft-like area may remain hypointense during enhancement
- enhancement pattern is otherwise similar to that seen on CT
- T2: cleft-like area may be markedly T2 hyperintense
Treatment and prognosis
Potential complications include:
- mass effect on adjacent structures (e.g. biliary tree, hepatic vessels)
- Kasabach-Merritt syndrome (a form of consumptive coagulopathy due to thrombocytopenia)
- rupture with hemoperitoneum
- atypisches Leberhämangiom
- Hämangiomatose der Leber
- Riesenhämangiom der Leber mit zentralem Thrombus