Figure 15b. Choroid plexus papilloma. (a, b) Transverse (a) and parasagittal (b) US images of a fetal head show a well-defined, lobular, hyperechoic mass (arrow) within the atrium of the right lateral ventricle. Hydrocephalus is also present. (c) Axial contrast-enhanced CT image of the brain demonstrates substantial enhancement of the mass (arrow). There is severe hydrocephalus with transependymal edema (arrowheads). (d) Photograph of the resected tumor shows the characteristic lobular contour.