Superficial siderosis is an uncommon late complication of the treatment of a childhood cerebellar tumor, but it is probably underrecognized. The diagnosis should be suspected in patients who present with slowly progressive sensorineural hearing loss and ataxia many years after eradication of a childhood cerebellar tumor.

Meningeal tumors occurring in a pediatric hospital over a period of 18 years were studied. The incidence of meningeal sarcomas was much lower than has been previously reported. A histologic subtype of meningiomas was found which has not previously been described. In these "sclerosing" tumors only a small portion of the lesion contained viable cells, most of which bore little resemblance to conventional meningothelial cells. The bulk of the lesions consisted of whorling collagen bundles produced by the tumor. All cases in which there was tumor invasion of the brain fell into this category. The prognosis for the sclerosing meningiomas was similar to conventional meningiomas, casting doubt on the value of brain invasion as a marker of malignancy in childhood meningiomas. The recognition of this histologic type may aid diagnosis, guide surgical management, and possibly make postoperative radiotherapy unnecessary.

BACKGROUND AND PURPOSE: MR imaging findings of aneurysm enlargement, aneurysm wall enhancement, perianeurysmal edema, and embolic phenomena following deployment of flow-diverting stents may be relevant to those patients who subsequently experience procedure-related intracranial hemorrhage. We sought to document the routine early postoperative MR imaging findings following flow-diverting stent insertion.