Intramedullary hobnail hemangioendothelioma of the conus.

Hemangioendotheliomas have only rarely been encountered in the neuraxis. Here, the authors present a case of an intramedullary hobnail hemangioendothelioma of the spinal cord, the first case described of this particular pathological entity in the neuraxis. The authors discuss their treatment and review the pertinent literature regarding management.

Extracranial carotid-vertebral bypass for endovascular access to complex posterior circulation aneurysms: a novel management approach.

BACKGROUND: Endovascular embolization is a desirable treatment option for complex posterior circulation aneurysms, particularly recurrent aneurysms or those in difficult-to-access surgical locations. However, endovascular access is occasionally prohibited by proximal vertebral artery (VA) occlusion or vessel tortuosity. One strategy in such instances involves creation of an extracranial bypass conduit to the distal VA. OBJECTIVE: To describe a novel strategy to allow for endovascular treatment of aneurysms at high risk for direct surgery. METHODS: Three cases of carotid-VA bypass performed to provide endovascular access to posterior circulation aneurysms were identified. The clinical indications, radiographic characteristics, operative technique, and outcomes were reviewed. RESULTS: Indications for bypass were previously clipped recurrent basilar tip aneurysm, previously coiled midbasilar aneurysm with compaction requiring stent placement, and distal intracranial VA aneurysm with iatrogenic vertebral dissection/occlusion after initial coil attempt. In all cases, routine endovascular access for primary or stent-assisted coiling was prohibited by VA tortuosity. Bypass with the use of interposition saphenous vein grafts was successfully performed to the C1-C2 region of the V2 segment without complications. The bypass was followed by successful endovascular treatment in all cases 2 to 6 weeks after surgery. In 1 patient, 2 recurrent treatments through the graft were subsequently performed for coil compaction. CONCLUSION: Extracranial carotid-VA bypass can be a valuable tool in the management of complex posterior circulation aneurysms. It is a safe and efficacious technique providing a conduit for repeated access to the posterior circulation in patients with otherwise prohibitive vertebral anatomy.

De novo malignant optic chiasm glioma with initial clinical response to steroids.

Malignant optic nerve glioma (MONG) is a rare but uniformly fatal disease that remains poorly understood. We describe a notable case of this rare disease occurring in the optic chiasm. Normal brain imaging and normal ophthalmic examination two years prior to diagnosis provide evidence for de novo genesis of MONG in our patient. Early response to steroids highlights the degree to which MONG can initially mimic inflammatory optic neuropathies and chiasmal syndromes. Our case also demonstrates a poor outcome with MONG even with current advanced therapy for glioblastoma including radiotherapy plus concomitant and adjuvant temozolomide (the EORTC/NCIC regimen) and bevacizumab.

Angiographic features of "brain sag".

OBJECT: Cerebrospinal fluid hypotension, or "brain sag," is a recently described phenomenon most commonly seen following craniotomy for the clipping of ruptured aneurysms along with preoperative lumbar drain placement. The clinical features and CT findings have been previously described. Clinical presentation can be similar to and often mistaken for cerebral vasospasm. In this study, the authors report on the angiographic findings in patients with brain sag. METHODS: Five cases of brain sag were diagnosed (range 1-4 days) after the surgical treatment of ruptured aneurysms at the University of Illinois at Chicago. All patients met the clinical and CT criteria for brain sag. Admission cerebral angiograms and subsequent angiograms during symptoms of brain sag were obtained in all patients. In 3 patients, angiography was performed after the resolution of symptoms. RESULTS: In all 5 patients, the level of the basilar artery apex was displaced inferiorly with respect to the posterior clinoid processes during brain sag. This displacement was significant enough to create a noticeable kink in the basilar artery ("cobra sign") in 3 patients. Other angiographic findings included foreshortening or kinking of the intracranial vertebral artery. In all patients, the posterior cerebral arteries were displaced medially and inferiorly. Three patients were treated for simultaneous severe radiological vasospasm. In 4 patients, the brain sag was recognized, and the patients' conditions improved when they were placed flat or in the Trendelenburg position, at times combined with an epidural blood patch. Patients with follow-up angiography studies after the symptoms had resolved displayed a reversal of the angiographic features. CONCLUSIONS: Brain sag appears to be associated with characteristic angiographic features. Recognizing these features may help to diagnose brain sag as the cause of neurological deterioration in this patient population.

Differences in the efficiency of reductive activation of methionine synthase and exogenous electron acceptors between the common polymorphic variants of human methionine synthase reductase.

Methionine synthase reductase (MSR) catalyzes the conversion of the inactive form of human methionine synthase to the active state of the enzyme. This reaction is of paramount physiological importance since methionine synthase is an essential enzyme that plays a key role in the methionine and folate cycles. A common polymorphism in human MSR has been identified (66A --> G) that leads to replacement of isoleucine with methionine at residue 22 and has an allele frequency of 0.5. Another polymorphism is 524C --> T, which leads to the substitution of serine 175 with leucine, but its allele frequency is not known. The I22M polymorphism is a genetic determinant for mild hyperhomocysteinemia, a risk factor for cardiovascular disease. In this study, we have examined the kinetic properties of the M22/S175 and I22/S175 and the I22/L175 and I22/S175 pairs of variants. EPR spectra of the semiquinone forms of variants I22/S175 and M22/S175 are indistinguishable and exhibit an isotropic signal at g = 2.00. In addition, the electronic absorption and reduction stoichiometries with NADPH are identical in these variants. Significantly, the variants activate methionine synthase with the same V(max); however, a 3-4-fold higher ratio of MSR to methionine synthase is required to elicit maximal activity with the M22/S175 and I22/L175 variant versus the I22/S175 enzyme. Differences are also observed between the variants in the efficacies of reduction of the artificial electron acceptors: ferricyanide, 2,6-dichloroindophenol, 3-acetylpyridine adenine dinucleotide phosphate, menadione, and the anticancer drug doxorubicin. These results reveal differences in the interactions between the natural and artificial electron acceptors and MSR variants in vitro, which are predicted to result in less efficient reductive repair of methionine synthase in vivo.