Case Report: Two cases of Typical Hepatic Hemangioma

In both cases MRI shows lesion as low signal in T1 weighted sequences, high signal in T2 weighted sequences with dynamic post-contrast images reveals early peripheral nodular enhancement with gradual centripetal filling and complete enhancement with retained contrast in delayed postcontrast images representing typical imaging features of hepatic hemangioma (Figures 1-4). Figure 1: US (a & b) showing hyper echoic sub capsular lesion in right lobe of liver. No color flow in (b). Corresponding MRI, T1 weighted image (c) reveal low signal and T2 weighted image (d) reveal high signal compared to normal liver parenchyma.


Imaging Findings US
First case referred for US and incidentally diagnosed focal sub capsular hyper echoic liver lesion.

CT
The second case referred for non-contrast CT KUB which demonstrates multiple low density liver lesions, more in right lobe.

MRI with and without Contrast
In both cases MRI shows lesion as low signal in T1 weighted sequences, high signal in T2 weighted sequences with dynamic post-contrast images reveals early peripheral nodular enhancement with gradual centripetal filling and complete enhancement with retained contrast in delayed postcontrast images representing typical imaging features of hepatic hemangioma (Figures 1-4).

Discussion
Hepatic haemangiomas, also known as hepatic venous malformations, are benign non-neoplastic solid hyper vascular liver lesions. It commonly diagnosed incidentally in asymptomatic cases of about 20%. Hemangiomas are often

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solitary, but multiple lesions may be present in both the right and left lobe of the liver in up to 40 percent of patients [2]. The size of hepatic hemangioma varies from a few millimeters to over 20cm. The majority are small (<5cm). Those larger than 5cm have been referred to as giant hemangiomas.  Although they can be diagnosed at any age, 60 to 80 percent of cases are diagnosed in patients who are between the ages of 30 and 50 years. Small hemangiomas are seen more frequently with helical CT, whereas they are easily overlooked on conventional CT because they becomes is dense to liver on late-phase images [2].
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.
The characteristic imaging findings for typical hemangioma are as follows [1]: On US it is usually well-defined hyper echoic.

b.
On unenhanced CT, seen as low density similar to that of vessels; on dynamic contrast-enhanced CT the lesion demonstrates peripheral globular enhancement and a centripetal fill-in pattern with the attenuation of enhancing areas similar to that of the aorta and blood pool. On MR imaging, the hemangioma shows high signal on T2-and heavily T2-weighted sequence and low signal in T1 weighted sequence which is comparable to signal of CSF in T1 and T2 weighted sequences. Dynamic post-contrast sequences reveal enhancing pattern same as CT with peripheral globular enhancement and a centripetal fill-in pattern with the attenuation of enhancing areas identical to that of the aorta and blood pool. Heavily T2 weighted images helps to detect even tiny focal hemangioma which can be overlooked in CT easily same as in our second case [3,4].
Hepatic haemangiomas are much more common in females, with a F:M of up to 5:1. Hepatic haemangiomas are thought to be congenital in origin, benign solid tumor and are almost always of the cavernous subtype. Blood supply is predominantly hepatic arterial, similar to other liver tumors. A peripheral location within the liver is most common [3].

SPECT
99Tc RBC labelled SPECT can be sensitive for larger lesions and typically demonstrate decreased activity on initial dynamic images followed by increased activity on delayed, blood pool images.

Differential Diagnosis
Typical hepatic hemangioma has characteristic imaging feature with relatively no differential diagnosis.