Hepatic Angiosarcoma Mimicking Sinusoidal Obstruction Syndrome: A Case Report

Hepatic angiosarcoma (HAS) is an uncommon malignant tumor that is often misdiagnosed because of its nonspecific presentation and overlapping imaging findings with benign vascular tumors. Sinusoidal obstruction syndrome (SOS) is a disorder of hepatic microcirculation, usually associated with myeloablative chemotherapy and hematopoietic stem cell transplantation. The clinical and pathological overlap between SOS and hepatic angiosarcoma may complicate the diagnosis of hepatic angiosarcoma, as illustrated by this case. We report the case of a sixty-year-old man who presented to the emergency department with progressive jaundice, abdominal discomfort, and weight loss exceeding 5% of his baseline. Laboratory workup revealed a predominantly cholestatic pattern, and serologies for viral, autoimmune, and metabolic liver diseases were negative. Also, there were no known risk factors for liver disease or SOS. Repeated imaging studies, including computed tomography (CT) and magnetic resonance imaging (MRI), revealed a large vascular hepatic lesion, suggestive of a benign lesion, and Doppler revealed findings compatible with SOS. Liver biopsy and hemodynamic studies indicated hepatic outflow obstruction. After clinical deterioration and expert multidisciplinary review of imaging and histology, malignant endothelial proliferation consistent with hepatic angiosarcoma was identified. Hepatic angiosarcoma can closely mimic SOS morphologically and hemodynamically. The absence of identifiable risk factors and the progressive evolution of hepatic changes should raise suspicion of malignancy, prompting multidisciplinary reassessment and careful histologic review.