Lollipop sign (hepatic epithelioid hemangioendothelioma)

The lollipop sign is seen in hepatic epithelioid hemangioendothelioma (HEHE). It represents hepatic/portal vein and/or their tributaries/branches tapering and terminating at or just within the edge of a well defined peripherally enhancing (or non-enhancing) lesion with an avascular core on CT or MRI images. This sign is a combination of two structures: the hypodense/hypointense well-defined tumor mass on enhanced CT/MRI images (the candy in the lollipop or target appearance) and the histologically occluded vein (the stick). This sign may improve the recognition of HEHE on cross-sectional imaging .

The target-like MR imaging appearance of HEHE tumors may be due to a central zone of fibrosis and a rim of cellular proliferation, with central signal hypointensity corresponding to hemorrhage, necrosis, or both, and peripheral hyperintensity corresponding to tumor cellularity and adjacent edema .