Hepatic Angiosarcoma: A Case Presentation

A 71-year-old male who presented with right upper quadrant pain was found to have hepatic angiosarcoma. We briefly review the epidemiology, presentation, imaging findings, and pathological diagnosis of hepatic angiosarcoma.


Introduction
Hepatic angiosarcoma, although rare, is the third most common primary liver malignancy. We present a case of a 71-year-old-male who presented with right upper quadrant pain and subsequently diagnosed with hepatic angiosarcoma during admission. We briefly discuss the epidemiology, imaging characteristics, and pathological diagnosis of hepatic angiosarcoma.

Case Presentation
A 71-year-old male with a remote history of prostate cancer and diabetes presented with a oneweek history of gradually worsening right upper quadrant abdominal pain. A contrastenhanced computed tomography (CT) scan ( Figure 1) was obtained in the emergency department, which revealed a large multifocal and diffusely enhancing mass within the liver. Laboratory workup revealed a slightly elevated aspartate aminotransferase, but was otherwise unremarkable. Tumor markers, including carcinoembryonic antigen, alpha fetoprotein, and carbohydrate antigen 19-9, were negative. The patient was subsequently admitted for further evaluation. Contrast-enhanced CT images in the axial (A) and coronal (B) planes demonstrate a diffusely enhancing, multifocal, heterogeneous, and infiltrative mass occupying most of the hepatic parenchyma. Mild capsular retraction (arrows) is noted secondary to the mass at the periphery of the liver. CT findings are highly concerning for a primary or metastatic hepatic malignancy.

FIGURE 1: Representative CT images
Magnetic resonance (MR) images obtained during admission showed a multifocal, predominantly T2 hyperintense hepatic mass, with heterogeneous enhancement and areas of necrosis ( Figure 2). Further imaging workup was negative for signs of extrahepatic metastatic disease. Results from a liver core biopsy ( Figure 3) demonstrate abnormal hepatic architecture with freely anastomosing vasculature and large, abnormal CD31+ endothelial cells surrounding small groups of hepatocytes-findings consistent with hepatic angiosarcoma.

Discussion
Hepatic angiosarcoma is the most common primary mesenchymal tumor of the liver and the third most common primary liver malignancy [1]. Hepatic angiosarcoma is a rare malignancy that accounts for less than 2% of all primary liver malignancies and appears more frequently in male patients older than 60 years of age [2]. Patients are typically asymptomatic until later stages of disease when they may present with abdominal pain or hemoptysis due to pulmonary metastasis. Patients who previously received thorium dioxide (Thorotrast) for imaging studies are at increased risk of developing hepatic angiosarcoma [3]. Additionally, occupational exposures to vinyl chloride monomer and arsenic are known to induce its formation.
On multiphasic contrast-enhanced CT and MR exams, hepatic angiosarcoma commonly appears as a multifocal tumor with variable enhancement patterns [2]. It is important to appreciate that hepatic angiosarcoma may share imaging characteristics with more common hepatic tumors. However, some differentiating characteristics do exist. For example, hepatic angiosarcoma with peripheral nodular enhancement can be distinguished from hemangioma by a lack of slow centripetal filling on delayed images [4]. Also, the poorly differentiated cells of hepatic angiosarcoma are less likely to retain hepatobiliary MR contrast agents to the extent of focal nodular hyperplasia [5][6][7].
On pathological analysis, hepatic angiosarcoma displays infiltrative vascular channels lined by atypical endothelial cells [8][9][10]. Lesions are typically multifocal, aggressive, and prone to hemorrhage which pose specific challenges against creating an efficacious treatment regimen. Short interval follow-up can be helpful for ambiguous lesions that do not meet criteria for biopsy.

Conclusions
Hepatic angiosarcoma is a rare entity that is difficult to distinguish from most other hepatic tumors and requires a pathological diagnosis. There are certain imaging characteristics, however, which may necessitate the inclusion of this entity on the differential for a hepatic mass.

Additional Information Disclosures
Human subjects: Consent was obtained by all participants in this study.

Conflicts of interest:
In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.