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FIG 1. 5-year-old girl who underwent imaging studies for a small bony prominence in the right temporal region after sustaining minor trauma.
A, Plain radiograph shows expansile lesion involving mainly the petrous portion of right temporal bone (arrow).
B, Technetium bone scan shows increased isotope uptake in the right temporal region (arrow).
C, Axial CT scan (bone window) shows an expansile tumor of the right temporal region with a coarse trabecular pattern and well-defined borders, involving the squamous, mastoid, and petrous portions of the temporal bone.
D, Axial unenhanced T1-weighted (500/20/2) MR image shows a large mass in the right temporal bone with well-defined borders, isointense signal in relation to brain, and scattered areas of high signal (arrow), most probably representing methemoglobin from thrombosed vessels (at histopathologic examination, the tumor lacked fatty tissue, a common cause of increased signal intensity).
E, Axial T2-weighted (2500/80/2) MR image shows the same lesion to be hyperintense relative to brain parenchyma, with evidence of flow voids, indicating the presence of vessels (arrow).
F, After contrast administration, axial T1-weighted (500/15/2) MR image shows marked enhancement of the lesion.
G, Anteroposterior view of the right external carotid angiogram (arterial and capillary phases, left and right, respectively) shows dilated vascular channels in the lesion, which is primarily supplied by the middle meningeal artery (arrow). The pooling of contrast material within the vascular channels of the lesion persisted well into the venous phase of the angiogram (not shown).
H, Photomicrograph shows vascular channels lined by plump endothelial cells having large, hyperchromatic nuclei, in a loose background stroma (hematoxylin eosin, original magnification x40).
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