Tumor bleeding from a de novo aneurysm associated with optic glioma.

Aneurysms in children are rare and potentially devastating lesions. The authors report the case of a 16-year-old girl with a complicated medical history related to a chiasmal glioma diagnosed at 18 months of age. She had previously received multiple modalities of radiation treatment, including external beam, proton therapy, and Gamma Knife. She presented with hemorrhage centered in the tumor and extending into the ventricular space. There was no subarachnoid blood. Magnetic resonance imaging demonstrated the hemorrhage and tumor anatomy. Magnetic resonance angiography revealed an aneurysm at the internal carotid artery bifurcation, but the lesion was more clearly delineated on CT angiography. A comparison MR imaging study obtained 6 months earlier, even in retrospect, did not show evidence of an aneurysm. This case illustrates the salient point that the clinician must search for vascular lesions in the patient with spontaneous "tumor bleeding," especially if that patient has risk factors for aneurysm formation. The authors also suggest that a CT angiogram is better at radiographically demonstrating an intratumoral aneurysm than an MR angiogram in this scenario.