Imaging features of hepatic angiosarcoma: retrospective analysis of two centers

Fig. 1. Ultrasound presentation of primary hepatic angiosarcoma. Patient 6. A Conventional ultrasound findings: A hypoechoic mass featuring clear boundaries and uneven internal echoes; B Grade I blood flow signal is visible within the tumor; C Contrast-enhanced ultrasoundperformance: At 14 s, the lesion exhibited circular enhancement from the periphery, slightly faster than the liver parenchyma; D At 20 s, the peak was reached, and a "vascular sign" (yellow arrow) appeared within the circular enhanced lesion, with slightly higher intensity than the surrounding liver parenchyma; E The tumor gradually reached its peak within 48 s, but the center remained incompletely filled; F During the 135-s delay period, the tumor displayed hypoechoic changes after regression

Fig. 2. Ultrasound presentation of a patient with single massive primary hepatic angiosarcoma (congenital type). Patient 5. This figure illustrates a patient with a massive primary hepatic angiosarcoma located on the surface of the liver. The tumor exhibits a cystic and solid structure, growing downwards and compressing the right appendage. A and B Conventional ultrasound findings: The tumor surrounds the liver's surface, displaying uneven internal ultrasound and unclear boundaries. An interstitial septal pattern is present, with abundant level 3 blood flow signals visible within. The resistance index is 0.39; C Contrast-enhanced ultrasound performance: At 14 s, the interstitial septation within the lesion enhanced faster than the liver parenchyma; D The peak was reached in 22 s, with the interstitial septation within the lesion exhibiting slightly higher intensity than the liver parenchyma; E The cystic part within the tumor compartment remained unfilled at 45 s, and the strength of the interstitial septation equaled that of the liver parenchyma; F After 105 s, the intensity of the interstitial septa within the tumor gradually subsided. L: Liver; T: Tumor

Fig. 3. Computed tomography presentation of primary hepatic angiosarcoma. A Patient 6: Low-density shadows are evident during the plain scan, with clear boundaries (yellow arrows); B Mild circular enhancement around the arterial phase, along with several punctate nodular enhancements within the lesion, varying in intensity and mixed; C and D In the portal and delayed phases, peripheral enhancement of the lesion gradually diminishes, while internal nodular mixed signals persist; E Patient 7: During the plain scan, peripheral high-density shadows are visible, with low-density shadows at the center and unclear boundaries (yellow arrows); F In the arterial phase, the lesion's contour gradually sharpens as the surrounding ring strengthens; G and H In the portal and delayed phases, the lesion's enhancement subsides, but the interior remains unfilled and structurally disordered; I Patient 6: Low-density shadows are noticeable during the plain scan, featuring clear boundaries; J Mild peripheral enhancement during the arterial phase, featuring a "vascular sign" (yellow arrow); K and L In the portal and delayed phases, peripheral enhancement gradually diminishes, yet the "vascular sign" remains…

Fig. 4. Positron emission tomography-computed tomography presentation of primary hepatic angiosarcoma. Depiction of low-density liver lesions with low fluorodeoxyglucose metabolism