What is new in epithelioid hemangioendothelioma of the liver?

An unusual hepatic vascular neoplasm has been delineated in recent years. It has characteristic morphologic features consisting of multiple nodules with relatively acellular centers which may be focally calcified. More peripherally there is a cellular zone containing elongated or plump tumor cells embedded in a fibromyxoid stroma. At the outer edge of the nodules, and particularly in vessels, the tumor cells may assume an epithelioid appearance. The tumor cells exhibit focally positive staining for Factor VIII related antigen and Weibel Palade bodies may be seen on electron microscopy. The tumor is malignant, but may have an indolent course over many years. It may be associated with hepatic cirrhosis and pulmonary osteoarthropathy. Other organs, particularly the lung and soft tissues are frequently involved.