Optic nerve compartment syndrome in a patient with optic nerve sheath meningioma.

PURPOSE: To report a patient with optic nerve (ON) sheath meningioma, unilateral optic disc swelling, and inhomogeneous cerebrospinal fluid (CSF) composition between lumbar CSF and CSF from the subarachnoid space (SAS) of the affected ON. METHODS: A 39-year-old woman presented with unilateral optic disc swelling and slight deterioration of visual function in the left eye. Extensive laboratory workup and magnetic resonance imaging (MRI) of the brain and orbits were performed. As radiotherapy was refused by the patient, ON sheath fenestration (ONSF) was offered and performed in order to stop deterioration. CSF from the SAS of the ON was sampled. RESULTS: Laboratory workup was within normal limits. MRI of the left orbit demonstrated enhancement of the dura in the precanalicular portion of the ON and distension of the SAS, most prominent in the bulbar portion of the ON. On lumbar puncture the opening pressure measured 19 (cm H2O). Compared to the lumbar CSF the CSF of the affected ON SAS showed markedly elevated measurements for albumin, IgG, and beta-trace protein. Visual function remained stable over a follow-up time of 18 months. CONCLUSIONS: Composition of CSF is considered to be homogenous throughout all CSF spaces. In this patient the authors found a marked concentration-gradient of albumin, IgG, and beta-trace protein between the CSF in the spinal canal and the CSF in the SAS of the affected ON. Based on the radiologic features of the left ON and the dissociated beta-trace protein concentrations in the CSF of the SAS of the ON and the lumbar CSF, the diagnosis of an ON sheath compartment syndrome due to an ON sheath meningioma was made.

Cerebrospinal fluid proteomic analysis reveals dysregulation of methionine aminopeptidase-2 expression in human and mouse neurofibromatosis 1-associated glioma.

Individuals affected with the neurofibromatosis 1 (NF1) tumor predisposition syndrome are prone to the development of multiple nervous system tumors, including optic pathway gliomas (OPG). The NF1 tumor suppressor gene product, neurofibromin, functions as a Ras GTPase-activating protein, and has been proposed to regulate cell growth by inhibiting Ras activity. Recent studies from our laboratory have shown that neurofibromin also regulates the mammalian target of rapamycin activity in a Ras-dependent fashion, and that the rapamycin-mediated mammalian target of rapamycin inhibition ameliorates the Nf1-/- astrocyte growth advantage. Moreover, Nf1-deficient astrocytes exhibit increased protein translation. As part of a larger effort to identify protein markers for NF1-associated astrocytomas that could be exploited for therapeutic drug design, we did an objective proteomic analysis of the cerebrospinal fluid from genetically engineered Nf1 mice with optic glioma. One of the proteins found to be increased in the cerebrospinal fluid of OPG-bearing mice was the eukaryotic initiation factor-2alpha binding protein, methionine aminopeptidase 2 (MetAP2). In this study, we show that Nf1 mouse OPGs and NF1-associated human astrocytic tumors, but not sporadic pilocytic or other low-grade astrocytomas, specifically expressed high levels of MetAP2. In addition, we show that Nf1-deficient astrocytes overexpress MetAP2 in vitro and in vivo, and that treatment with the MetAP2 inhibitor fumagillin significantly reduces Nf1-/- astrocyte proliferation in vitro. These observations suggest that MetAP2 is regulated by neurofibromin, and that MetAP2 inhibitors could be potentially employed to treat NF1-associated tumor proliferation.

Case of pediatric optic pathway oligodendroglioma presenting widespread invasion and dissemination in the cerebrospinal fluid.

Optic pathway oligodendrogliomas are a rare form of pediatric intracranial tumor. A 10-year-old girl presented with symptoms of hydrocephalus and seizure. Head computed tomography and magnetic resonance images showed hydrocephalus, chiasmal tumor, and enlarged and tortuous optic nerves. The tumor was partially removed by operation and diagnosed as oligodendroglioma. Operatively, there was evidence of cerebrospinal fluid dissemination in the sylvian fissure indicating widespread invasion. After the operation, Packer's regimen (vincristine and carboplatin therapy) was administered. However, magnetic resonance images obtained 2 months after the operation revealed enlargement of the original tumor and the appearance of new lesions, and treatment was changed to irradiation and temozolomide therapy according to the presence of a high-grade glioma. Two years after the operation, the patient is free of neurological symptoms, and the tumor is controlled with partial response. This is the first report of pediatric optic pathway oligodendroglioma presenting widespread invasion and cerebrospinal dissemination.