INTRODUCTION: Angiosarcomas are uncommon and aggressive endothelial cell tumors which arise from vessels or lymphatic tissue. The common sites are the head, neck, extremities and breast. It can spread hematogenously to lung, liver, lymph nodes, bones and rarely bowel (Lancet oncol 2010; 11:984). Primary hepatic angiosarcoma (HAS) is a rare and aggressive soft tissue tumor with dismal outcome. The known etiologies include exposure to vinyl chloride monomers, thorium oxide, arsenic, anabolic steroids, history of neurofibromatosis and hemochromatosis. CASE DESCRIPTION/METHODS: An 83-year-old male with a history of myasthenia gravis presented with abdominal distention, peripheral edema and intermittent encephalopathy for one month. Myasthenia gravis was treated with prednisone and azathioprine. Labs showed anemia, thrombocytopenia and elevated transaminases (ALT 33, AST 66, ALP 82, total bilirubin 0.7), INR was 1.2. Further testing for viral hepatitis and autoimmune panel were negative. A CT abdomen showed a nodular liver, ascites, innumerable hypoattenuating liver masses with a peripherally enhancing lesion (2.8 cm) and a hyper-vascular 2 cm mass in the right lobe. The head neck and chest imaging were negative for primary malignancy or metastatic disease. Ascites fluid analysis was consistent with portal hypertension. The liver biopsy suggested primary hepatic angiosarcoma which was confirmed on immunohistochemical staining. The patient decided not to opt for treatment and hospice was initiated. DISCUSSION: The only known risk factors in our case were advanced age and concurrent use of immunosuppressive agents. There is no specific tumor marker and a British study had shown negative alpha feto-protein for all the angiosarcoma cases (Gut 1987; 28:669). On immunohistochemistry the tumor cells express CD31, CD34, von Willebrand factor, vascular endothelial growth factor, and Ulex europaeus agglutinin 1. HAS manifests clinically at an advanced stage and life expectancy is usually 6 months. The (AASLD) considers angiosarcoma as a contraindication to liver transplantation (Hepatology 2014; 59:1147). Tumor resection is favorable only in subjects with a solitary tumor involving one hepatic lobe. Chemotherapy or locoregional therapy in surgically non-resectable tumors has shown no survival benefit. Hepatic angiosarcoma can develop in elderly, immunosuppressed individual. It can present as incidental hepatic mass or decompensated liver disease. Liver biopsy with immunohistochemical staining is the best diagnostic test.Figure 1.: CT abdomen axial section showing peripherally enhancing mass (red arrow) in right hepatic lobe.Figure 2.: CT abdomen axial section showing right hepatic lobe hypervascular lesion (red arrow) and diffuse hypoattenuating lesions.Figure 3a.: Liver biopsy Hematoxylin-eosin (H&E) staining stain of left hepatic lobe showing endothelial cells with enlarged hyperchromatic nuclei lining the vascular channels; 3b: Immunohistochemical stain shows that the tumor cells are positive for vascular antigen CD34.