Figure 7f. Retinoblastoma in a 7-year-old girl who complained of blurry vision in her right eye. (a) Photomicrograph (original magnification, x400; H-E stain) shows Flexner-Wintersteiner rosettes with central lumina (straight arrows). Numerous mitotic figures are noted (arrowheads) as well as areas of necrosis (*). Also note the central focus of proliferative vessels with plump endothelial cells (curved arrow). (b) Photomicrograph (original magnification, x20; H-E stain) shows a homogeneous mass of tumor cells in the posterior globe (*) that invade the optic nerve (arrows). (c) Photomicrograph (original magnification, x100; H-E stain) shows basophilic neoplastic cells in the optic disc (*) crossing the lamina cribrosa (arrows) into the optic nerve (arrowheads). (d) Photograph of the sectioned gross specimen shows an irregular whitish mass (*) arising from the thickened retina (arrowhead). (e) Ultrasonographic (US) image obtained with a high-frequency linear transducer shows the heterogeneous, nodular mass (arrow) in the globe apposed to the retina and posterior to the lens (arrowhead). (f) US image shows posterior acoustic shadowing (arrow).