Primary hepatic angiosarcoma: multi-institutional comprehensive cancer centre review of multiphasic CT and MR imaging in 35 patients.

OBJECTIVE: To assess the imaging features of primary hepatic angiosarcoma on multiphasic CT and MR.

METHODS: Multi-institutional review identified 35 adults (mean age, 57.1 years; 22M/13F) with pathologically proven hepatic angiosarcoma and pretreatment multiphasic CT (n = 33) and/or MR (n = 7).

RESULTS: Multifocal hepatic involvement was seen in all 35 cases, with at least 10 lesions in 74.3% (26/35). Mean size of the dominant mass was 8.9 ± 4.7 cm (range, 2.6-20 cm). Individual nodules were typically circumscribed. Arterial-phase foci of hypervascular enhancement without washout were seen in 89.7% (26/29). Heterogeneously expanding foci of enhancement generally followed blood pool in 88.6% (31/35). Progressive centripetal (n = 16) or diffuse "flash-fill" (n = 4) enhancement pattern resembling cavernous haemangiomas predominated in 20 cases, whereas a "reverse haemangioma" centrifugal pattern predominated in 11 cases. Rapid interval growth was seen in 24 (96.0%) of 25 cases with serial imaging. Vascular invasion was not seen in any case. Underlying cirrhotic morphology was seen in 42.3% (15/35).

CONCLUSION: Primary hepatic angiosarcomas typically manifest as aggressive multifocal tumors containing small heterogeneous hypervascular foci that progressively expand and follow blood pool. The appearance can mimic cavernous haemangiomas, but distinction is generally possible. In the setting of cirrhosis, lack of tumour washout and vascular invasion argue against multifocal hepatocellular carcinoma.

KEY POINTS: • Hepatic angiosarcoma manifests on CT and MR as rapidly progressive multifocal tumours • Multiphasic imaging demonstrates hypervascular foci that progressively expand and follow blood pool • Enhancement pattern can resemble cavernous haemangiomas or show a "reverse" centrifugal pattern • Lack of tumour washout of hypervascular lesions argues against multifocal hepatocellular carcinoma • Careful assessment of the cross-sectional imaging findings may suggest the diagnosis.