Hepatic Epithelioid Hemangioendothelioma in Taiwan: A Clinicopathologic Study of Six Cases in a Single Institution Over a 15-Year Period

Background/Purpose: Hepatic epithelioid hemangioendothelioma (HEH) is a rare vascular tumor of the liver typically with a slow but progressive course. We report the clinical and immunohistochemical characteristics of six cases from our institution between 1993 and 2008. Methods: We searched the files of the Department of Pathology in National Taiwan University Hospital from January 1993 to December 2008 and found six cases of primary HEH. The clinical data were reviewed. The microscopic findings of each case were listed and analyzed. Confirmational immunoperoxidase stains were performed with antibodies against two endothelial markers (CD31 and CD34) and one epithelial marker (AE1/AE3 or cytokeratin). Results: There were five female patients and one male patient with HEH, and the mean age was 45.3 years (range, 25-86 years). Most patients were asymptomatic and one third of cases presented as right costal or abdominal pain. Anemia was the most common laboratory abnormality. Liver failure developed at the advanced diffuse stage. Imaging studies revealed three different patterns as single nodular, multiple nodular, or diffuse types, reflecting different stages of disease and clinical symptoms. Microscopic findings included intracyto-plasmic vascular lumen formation (100%), sinusoidal spreading (100%), vessel obliteration (66.7%), necrosis (66.7%), and cellular pleomorphism (16.7%). All cases expressed endothelial markers of CD31 and CD34, reflecting their vascular nature. Two patients received surgical treatment including partial liver resection and liver transplantation. Tumor recurrence developed 8 and 17 months later, respectively. Conclusion: HEH showed insidious growth and frequent multicentricity, making early diagnosis and tumor resection difficult. Definite diagnosis totally relies on pathologic study. Tumor progression to hepatic failure is slow. Liver transplantation is currently the most prevalent treatment modality for HEH, but experience in Taiwan is limited due to the rarity of this disease.