"incidence is estimated at 1–2 cases per million people"
"T1: hypointense lesions relative to normal liver parenchyma on unenhanced T1-weighted images"
"T2: heterogeneously increased signal intensity, with a white target sign in which the bright central core is surrounded by a peripheral, slightly hyperintense halo"
"T1 C+ (Gd): some lesions demonstrate either a peripheral halo or a target-type enhancement pattern after administration of a gadolinium-based contrast agent, with an occasional thin peripheral hypointense rim"
"The histology can mimic metastatic carcinoma, cholangiocarcinoma or angiosarcoma and immunohistochemistry is key to diagnosis. HEHE typically expresses vascular markers such as CD31, CD34, and factor VIII-related antigen, and are negative for cytokeratins. The most common genetic abnormality is the CAMTA1-WWTR1 fusion gene 11,13."
"Usually seen as predominantly hypoechoic hepatic lesions; however, they can also have mixed echotexture or be predominantly hyperechoic."