INNV-20. ELEVATED INTRACRANIAL PRESSURE WITHOUT HYDROCEPHALUS IN PATIENTS WITH NEUROFIBROMATOSIS 2

Abstract

Abstract BACKGROUND Neurofibromatosis 2 is a tumor predisposition syndrome associated with multiple tumors of the central and peripheral nervous systems. Schwannomas and meningiomas are commonly observed. The occurrence of communicating hydrocephalus in this population has been observed clinically but not characterized in the literature. METHODS We present a retrospective case series of patients with NF2 and communicating hydrocephalus followed in the Neurofibromatosis clinic at MD Anderson Cancer Center. RESULTS We identified 11 patients in our Neurofibromatosis clinic with symptomatic elevation in intracranial pressure (ICP). All patients presented with worsening headaches, while six patients also presented with visual complaints leading to the diagnosis of elevated ICP. Dedicated venous imaging with either MRV or CTV was available for review in five patients. Occlusion or stenosis of the venous system (dural venous sinuses or internal jugular vein) was seen in nine patients. All patients had evidence of plaque-like meningiomas, and two patients had cervical schwannomas. Only one patient had radiographic evidence of obstructive hydrocephalus. All patients were treated for symptomatic elevated ICP with placement of a ventriculoperitoneal (VP) shunt. Three patients received acetazolamide prior to shunting, while one patient received acetazolamide after shunt placement. Seven (7/11) patients had documented improvement or resolution of headache after VP shunt placement. Two (2/6) patients had documented improvement or resolution of visual complaints. CONCLUSIONS We present 11 patients with NF2 who developed symptomatic elevation in ICP, ten patients without evidence of obstructive hydrocephalus and one with obstructive hydrocephalus. We hope to raise awareness of this clinical phenomena, previously uncharacterized in the literature. We propose a multifactorial mechanism involving plaque-like meningiomas, venous sinus stenosis, obstruction of cerebral venous outflow and cervical/jugular schwannomas in the development of symptomatic elevated ICP without evidence of obstructive hydrocephalus in patients with NF2.