What abnormalities are shown on the contrast-enhanced computed tomography (CT) scan in Figure 1? There are non-specific, hypodense lesions in both the right and left lobes of the liver. The patient was a 33-year-old white woman who, 3 years previously, had a right mastectomy for a grade 3 ductal carcinoma of the breast. This was followed by a standard chemotherapy regimen. She was thought to have liver metastases but a CT-guided biopsy of one of the liver lesions revealed epithelioid hemangioendothelioma. She was treated by liver resection and subsequently had radiofrequency ablation. The image in Figure 2 shows the histological appearance of epithelioid hemangioendothelioma (hematoxylin & eosin stain) in a different patient who was initially thought to have colon cancer with widespread peritoneal and liver metastases. In this patient, immunoperoxidase stains were positive for CD31, CD34 and vimentin.
Epithelioid hemangioendothelioma is a rare, low-grade malignant neoplasm of endothelial cells. The tumor is usually located in the liver but can involve other organs such as lung, soft tissue and bone. The cause of the neoplasm is unknown. Women are more likely to be affected than men and the mean age at diagnosis is 30–40 years. Up to 40% of patients are asymptomatic but have liver lesions on imaging studies. In the remainder, symptoms include abdominal discomfort, abdominal pain and weight loss. Approximately two-thirds of patients have an elevation in the serum level of alkaline phosphatase. With abdominal imaging, the typical feature is multiple liver lesions ranging up to 14 cm in size that can be readily confused with multiple metastases. A minority of patients have patchy hepatic calcification. The tumor has distinctive histological features but can be misdiagnosed by the pathologist. Immunostaining is helpful as almost all these tumors are positive for factor VIII-related antigen (FVIII-RAg), CD31, CD34 and vimentin. The clinical course of patients with epithelioid hemangioendothelioma is highly variable. The 5-year survival rate is at least 40% and there are well-documented cases of spontaneous regression. Treatment modalities that appear to improve survival include radical hepatic resection and liver transplantation. The role of chemotherapy and radiotherapy continues to be unclear.