Hepatic angiosarcoma

Hepatic angiosarcoma is a rare malignancy but is still the third most common primary liver tumor. They have a variable appearance on both CT and MRI, reflecting the pleomorphic histological nature. Prognosis is very poor, with survival uncommon beyond one year from diagnosis. 

Terminology

Hepatic angiosarcoma was previously known as Kupffer cell sarcoma. 

Epidemiology

Hepatic angiosarcomas account for ~1% of primary liver tumors. Most commonly occurs in patients in their 60-70s with a male predominance (M:F = 4:1) ^1-3. 

Clinical presentation

Patients typically have non-specific abdominal symptoms and may present with an abdominal mass or hepatomegaly. Patients can also present with spontaneous rupture and hemoperitoneum ^1,5. 

Pathology

Hepatic angiosarcomas arise from malignant spindle cells of endothelial origin. Metastases are common at presentation, affecting lung and spleen.

Etiology

Most hepatic angiosarcomas arise spontaneously, although hemochromatosis and neurofibromatosis type 1 have also been associated.

Environmental exposure to Thorotrast, arsenic, ionizing radiation and vinyl chloride have been implicated as risk factors, but such exposure is now rare.

Histology

Histology demonstrates varied appearances of solid nodules/masses or as sinusoidal or cavernous spaces. 

Radiographic features

Hepatic angiosarcomas most commonly present as multiple masses but can occur as a single heterogeneous mass ^2,4. 

CT

• hypoattenuating masses (some may be hyperattenuating reflecting hemorrhage) on both non-contrast and contrast-enhanced CT
• nodular enhancement is common

MRI

Findings reflect the hemorrhagic nature of angiosarcomas with fluid-fluid levels often a feature ²: 

• T1/T2: heterogeneous areas of high signal reflecting mixed tumor and hemorrhage
• T1 C+ (Gd): heterogeneous enhancement with progressive filling

Nuclear medicine

• avid on FDG PET-CT ⁵

Treatment and prognosis

It typically rapidly progresses with metastases and high recurrence rate although partial liver resection may be successful if it is confined to one lobe of the liver. 

Prognosis is poor with hepatic angiosarcomas being resistant to chemotherapy and radiation therapy. Median survival is less than six months and survival beyond one year is rare.