Fig 12.

Increased vascularity in a tumor. This 8-year-old girl presented with headache, nausea, ataxia, and vomiting. CT imaging demonstrated a large mildly lobulated hyperattenuated mass arising from the right lateral ventricle with marked surrounding white matter edema and hydrocephalus. Axial postcontrast T1-weighted image (A) shows patchy irregular enhancement of the lesion. The mass is largely isointense on the T2-weighted image (B), except for a circular dark region (open arrow) that likely reflects an area of hemorrhage. On SWI (C), the hemorrhage (open arrow) is markedly hypointense due to “blooming” effect. There are also small irregular hypointense areas in the posteromedial tumor, suggestive of increased venous vascularity (arrow). A mildly enlarged subependymal vein (arrowhead) is seen on all MR images. Pathology revealed a choroid plexus tumor with areas of anaplasia, including a high proliferative index, necrosis, and loss of architecture; most are consistent with choroid plexus carcinoma.