Fig. 3

Histopathological and immunohistochemical staining of the tumor. a Diffuse spindle cells with ‘anter’-like vessels on background (HE staining; original magnification: × 200). b Haphazardly arranged heterotypical spindle cells with variable collagenous and ‘staghorn’ vessels in the background (HE staining; original magnification: × 200). c Frequent mitoses (HE staining; original magnification: × 400). d Onyx embolization material with the appearance of granular black pigment (tantalum powder) (white arrows) in the center of the vessels (HE staining; original magnification: × 50). e Tumor cells positive for CD34 (original magnification: × 200). f Tumor cells positive for Ki-67 (approximately 15%) (original magnification: × 200). HE hematoxylin and eosin