Radiologic Findings CT US MR 5.1 cm low attenuated mass in S8 with multiple satellite nodular lesions with delayed enhancement and capsular retraction 3.5 cm lobulated low attenuated mass in spleen with centripetal enhancement US Heterogeneous hyperechoic mass with multiple hyperechoic nodules Heterogeneous hypoechoic splenic mass MR Heterogeneous high SI mass and multiple nodular lesions with central low SI on T2WI, low SI on T1WI, diffusion restriction Delayed enhancement and capsular retraction Heterogeneous high SI with multiple dark SI foci in spleen on T2WI, low SI on T1WI

Differential Diagnosis Intrahepatic cholangiocarcinoma Angiosarcoma Epithelioid hemangioendothelioma Homogeneous, irregular peripheral enhancement with gradual centripetal enhancement Satellite nodules, capsular retraction, vascular encasement with the tumor thrombus 4cm 이상의 IHCC의 경우, centripetal type의 mild enhancement를 보이기도 함, but 대개 중심부 scar는 그래도 조영이 안되는데, 이 case에서도 일부 central portion이 조영 안됨. Meta 있어서 cavernous hemangioma는 가능성이 떨어지고 T2WI에서 SI이 너무 낮으면서 heterogeneous함., shape도 bizzare하니까 아님. Arterial phase CT scan shows a tumor with ragged rim enhancement at the periphery (arrow)

Differential Diagnosis Angiosarcoma M:F = 4:1, 50-70 years Heterogeneous, irregular mass, with progressive centripetal enhancement Hemorrhage and fibrous septa within the tumor : common Common metastasis at initial diagnosis : spleen (m/c), lung MR : contains areas of high SI on T1WI, markedly heterogeneous SI on T2WI centrally septal-like progressive enhancement Angiosarcoma in a 64-year-old woman. Unenhanced CT shows a lobular heterogeneous low-density mass in each lobe of the liver, ill-defined margin with curvilinear calcification (black arrow) in the left lobe and clear margin in the right lobe. Enhanced CT reveals peripheral nodular enhancement of the two lesions. On delayed images, most areas of tumors become isodense with normal liver, and only some areas of lesion in the left lobe remain hypodense. (The regions of interests are seen in each lobe of the liver)

Differential Diagnosis Epithelioid hemangioendothelioma M:F = 2:3, 30-40 years, 1/3 : extrahepatic metastasis (m/c : lung) Peripheral multiple nodules (82%) → extensive confluent mass Marginal e’ on arterial phase → isodense to parenchyma on or target / peripheral halo e’, especially large lesions Capsular retraction (25%), calcification (20%) MR : hypointense on T1WI, heterogeneously hyperintense on T2WI peripheral halo or target-type enhancement pattern, occasionally thin peripheral hypointense rim Lung 외에 abdominal LNs, omentum, mesentery, peritoneum Epithelioid hemangioendothelioma in a 56-year-old woman. Unenhanced CT shows multiple, discrete, peripheral, low-attenuation lesions, with compensatory hypertrophy in the left lobe of liver, associating with pleural effussion in both sides. (b–d) Contrast-enhanced multiplephase CT shows partial areas of lesions are progressive reinforcement (black arrow) with flattening retraction of the liver capsule (d) (white arrow), associating with pleural effussion in both sides

Pathologic Diagnosis Liver, needle biopsy : Angiosarcoma, well differentiated 분홍색으로 보이는 부분이 stroma Atypism을 보이는 multiple lining endothelium으로 둘러싸인 irregular dilated space가 관찰되며, 이런 점이 Kaposi’s sarcoma나 hemangioendothelioma에는 없는 점이다. CD31, CD34, Facter VIII등 endothelial cell marker에 모두 positive이고, vessel이 증식된 종양 즉 well-differentiated이지만 variable size의 blood vessel과 stroma를 가지는 atypical cell들로 구성된 vasoformative tumor로 well-differentiated angiosarcoma. CD31 CD34 Factor VIII

Hepatic Angiosarcoma Rare hepatic malignancy, but m/c primary hepatic sarcoma Only 4% of all the angiosarcomas of different origins 1.8% of all hepatic malignancies Associated with chronic exposure to thorotrast, polyvinyl chloride, arsenic, androgenic anabolic steroid, and radiation 50-70 years, M:F=4:1 Rapidly progress (median survival : 6 months) Most patients are diagnosed at advanced stage : lung, spleen Clinical presentation Abdominal pain, fatigue, weight loss Hepatomegaly, ascites, thrombocytopenia 60대 남성에 호발 thrombocytopenia (d/t PLT sequestration) 대부분에서 진단 당시 meta (+), 2002 radiology 보고에는 23%에서 pulmonary meta, 46%에서 splenic meta

Hepatic Angiosarcoma Histopathology Consisted of spindle or pleomorphic cells : vasoformative, forming poorly organized vessels Fibrosis and deposition of hemosiderin Predominantly located near the liver surface Classified into 4 types according to growth pattern 1. Multiple nodules 2. Large solitary mass 3. Mixed pattern of a dominant mass with nodules 4. Hepatomegaly with diffuse infiltrating micronodular tumors : rare AFP and CEA : not elevated 이전에는 Vascular channel들 때문에 cavernous hemangioma와 유사하게 보일 수 있다고 하였으나, 현재 enhancement pattern등에 따르면 구분 확실히 가능

Imaging Features of Hepatic Angiosarcoma CT findings Hypoattenuating mass on unenhanced CT (17-27 % hemorrhage → hyperdense) Curvilinear calcification Variety of findings on contrast-enhanced CT Progressive centripetal enhancement Bizarre shapes, central enhancement or peripheral ring-shaped enhancement → does not resemble benign cavernous hemangioma (a) Unenhanced CT shows a lobular heterogeneous low-density mass in each lobe of the liver, ill-defined margin with curvilinear calcification (black arrow) in the left lobe and clear margin in the right lobe. (b) Enhanced CT reveals peripheral nodular enhancement of the two lesions. (c) On delayed images, most areas of tumors become isodense with normal liver, and only some areas of lesion in the left lobe remain hypodense. (The regions of interests are seen in each lobe of the liver)

Imaging Features of Hepatic Angiosarcoma Many angiosarcoma lesions were hypoattenuating to the liver on both arterial and portal venous phase images (Figs. 1–5). A few were hyperattenuating on arterial phase images (Figs. 1, 3, and 6), some becoming isoattenuating on portal venous phase images (Fig. 1), clearly different from blood pool attenuation. AJR 2000; 175:165-170

Imaging Features of Hepatic Angiosarcoma MR findings Low SI on T1WI, markedly heterogeneous high SI on T2WI Area of high signal intensity on the T1WI : hemorrhage With central low SI on T2WI : suggest hemorrhage and fibrous septa within the tumor Centrally septal-like progressive enhancement Transverse T1-weighted spin-echo (266/14) MR image shows a massive tumor (arrow) in the vicinity of a chronic organized subcapsular hematoma (arrowheads). The lesion contains focal areas of high intensity, which suggest hemorrhage. (d) Transverse fat-saturated T2-weighted fast spin-echo (8,571/70) MR image shows the marked heterogeneous appearance of the lesion (arrows) and hematoma (arrowheads)