Spontaneous Giant Pseudomeningocele in the Middle Cranial Fossa as a Cause of Pulsatile Proptosis.

The authors report a case of a 70-year-old man who presented with a long history of left pulsatile proptosis, irritation, and a pressure sensation behind the eye. Initial computed tomography brain demonstrated the presence of a suspected ethmoid sinus mucocele. Endoscopic sinus surgery was performed to drain the mucocele. On cautious opening of the nasal mucosa, cerebrospinal fluid was encountered requiring subsequent repair with local mucosal flap and fat graft. On further magnetic resonance imaging, the lesion was confirmed to be giant pseudomeningocele arising from the sphenoid sinus, with extensive invasion and erosion of the middle cranial fossa including the left lateral orbital wall. Here, the authors report, to the best of their knowledge, the first case of spontaneous giant pseudomeningocele in the middle cranial fossa causing pulsatile proptosis. In examining this case, the authors will also discuss the pathogenesis, diagnosis, and management of giant pseudomeningoceles, especially in the situation of a misdiagnosis.

Progressive post traumatic tearing of an arachnoid cyst membrane resulting in intracystic and subdural haemorrhage.

We report the case of a 43-year-old man with a middle cranial fossa arachnoid cyst who presented post trauma with neurological symptoms. The initial CT scan of the brain did not detect acute changes in the arachnoid cyst but subsequent imaging revealed abnormalities which progressed over time. Arachnoid cysts are usually a benign and incidental finding. Rare complications such as intracystic haemorrhage and subdural haemorrhage can occur. It is important to be aware of these complications so that patients with arachnoid cysts are appropriately investigated when presenting with neurological symptoms.

Pediatric dural arteriovenous malformations.

Pediatric dural arteriovenous malformations (dAVMs) are rare lesions that have a high mortality rate and require complex management. The authors report 3 cases of pediatric dAVMs that presented with macrocrania and extracranial venous distension. Dural sinus thrombosis developed in 2 of the cases prior to any intervention, which is an unusual occurrence for this particular disease. All 3 cases were treated using staged endovascular embolization with a favorable outcome in 1 case and a poor outcome in the other 2 cases. Complications developed in all cases and included dural sinus thrombosis, parenchymal hemorrhage, intracranial venous hypertension, and seizures. The strategies and challenges used in managing these patients will be presented and discussed, along with a review of the literature. While outcomes remain poor, the authors conclude that prompt treatment with endovascular embolization provides the best results for children with these lesions. A well-established venous collateral circulation draining directly to the internal jugular veins may further improve the rate of favorable outcome after embolization.

Anatomic comparison of nasal versus lateral surgical access to the petrous apex.

To compare anatomic access to the petrous apex via the nasal and lateral approaches. Hundred consecutive fine-cut CT temporal bones at the Royal Melbourne Hospital from July 27, 2007 to October 30, 2010 were reviewed. Easy lateral access allowed use of a 4 mm burr past vital structures. Easy nasal access was defined as sphenoid pneumatization to/beyond the posterior sella and laterally beyond the maxillary/vidian nerves. Three patients with petrous apex pathology were also reviewed. Easy lateral and nasal access occurred in 74 (37%) and 79 (39.5%) sides, respectively. Easy nasal and lateral access were not strongly correlated (r = 0.10, P = 0.15). A well-pneumatized mastoid (62.5%) was strongly correlated with a large sphenoid (63%, P < 0.001). Pneumatization of the mastoid corresponds to sphenoid sinus size. However, surgical access to the petrous apex is more determined by proximity of vital structures. Easy surgical access via the nasal or lateral approaches was not strongly correlated. Petrous apex lesions requiring surgery should be considered for both approaches.

Primary diffuse leptomeningeal gliosarcomatosis with a sphenoid/sellar mass: confirmation of the ectopic glial tissue theory?

Gliosarcoma is a rare glioblastoma variant, classically arising in the cerebral hemispheres. We report a patient with primary diffuse leptomeningeal gliomatosis (PDLG) with a sphenoid sinus and sellar mass. An 84-year-old woman presented with progressive headache and right-sided visual failure, associated with ipsilateral oculomotor nerve palsy and left temporal field loss. Neuraxial MRI showed a large lesion within the sphenoid sinus and sella resulting in chiasmal compression, and diffuse cranial and spinal leptomeningeal enhancement. Endoscopic transphenoidal biopsy and debulking of the sphenosellar lesion was performed, and gliosarcoma was diagnosed on histopathological examination. The patient was palliated due to poor performance status. To our knowledge, this is the only report of gliosarcoma within the paranasal sinuses and the second report of PDLG where the histological analysis has confirmed gliosarcoma. We believe this adds significant weight to the theory that heterotopic nests of glial tissue, in this instance within the sphenoid or sella, are the putative origin of PDLG.

Ventriculocystostomy and endoscopic third ventriculostomy/shunt placement in the management of hydrocephalus secondary to giant retrocerebellar cysts in infancy.

Hydrocephalus secondary to giant retrocerebellar cysts in infancy is a challenging condition and many treatment options exist. The authors report on 3 consecutive cases involving infants under the age of 6 months treated successfully with ventriculocystostomy in combination with direct hydrocephalus treatment (endoscopic third ventriculostomy or shunt placement). They describe the operative procedure, the surgical morbidity, and outcome in each case and review the literature regarding surgical approaches to this condition.

Relative contributions of the middle meningeal artery and superficial temporal artery in revascularization surgery for moyamoya syndrome in children: the results of superselective angiography.

OBJECT: The authors used postoperative superselective angiography to assess the relative contributions of the middle meningeal artery (MMA) and the superficial temporal artery (STA) to revascularization following surgery for moyamoya syndrome in children. METHODS: Using the neurosurgical database at the Hospital for Sick Children, the authors reviewed the clinical and pre- and postoperative angiographic records obtained in patients with moyamoya syndrome undergoing superselective angiography. Patients were 16 years of age or younger and were undergoing revascularization surgery for moyamoya syndrome during the study period. Lateral internal carotid artery, external carotid artery, STA, and MMA angiograms were analyzed in the late arterial phase to assess the relative contributions of the STA and MMA to overall revascularization as determined by the external carotid artery injection. RESULTS: The total moyamoya surgical revascularization experience at the Hospital for Sick Children over a 12-year period (May 1996-December 2008) comprised 33 patients (20 girls and 13 boys) undergoing a total of 50 craniotomies. A decision was made in 2001 to perform superselective angiography postoperatively in patients with moyamoya syndrome. Superselective angiography was identified to have been performed postoperatively in 12 patients and 18 treated hemispheres, and it demonstrated that the MMA contributed more significantly than the STA in 11 (61%) of the 18 hemispheres. Seven patients were Asian, 3 patients had neurofibromatosis Type 1, 1 had Down syndrome, and 2 had no apparent risk factors (1 patient was Asian and had neurofibromatosis Type 1). Stroke had occurred in 58% of patients and transient ischemic attacks in 50% prior to surgery. Within the first 30 days of surgery, there were 2 episodes of stroke (11.7% per surgically treated hemisphere and 18.2% per patient). Seventy-eight percent of hemispheres surgically treated exhibited excellent revascularization (Matsushima Grade A) on follow-up angiography, and there were no strokes documented in any patients more than 1 month after surgery, in a long-term follow-up of mean 4.1 years. CONCLUSIONS: The contributions of the MMA to revascularization after pial synangiosis for moyamoya syndrome are significant and may frequently exceed the contribution of the STA when surgery is performed with preservation of dural vasculature and dural inversion.

Neurosurgical implications of achondroplasia.

OBJECT: Achondroplasia is the most common form of human short-limbed dwarfism. The pediatric neurosurgeon is frequently required to treat children with achondroplasia who have hydrocephalus, cervicomedullary compression (CMD), and spinal canal stenosis. Accordingly, the authors have reviewed the experience of neurosurgery in children with achondroplasia at The Hospital for Sick Children. METHODS: The medical records and neurosurgery database at The Hospital for Sick Children were searched to identify all children with achondroplasia who underwent at least 1 neurosurgical procedure between 1956 and the present. RESULTS: Twenty-nine children with achondroplasia underwent 85 surgical procedures: 52 for CSF diversion in 12 patients, 20 for CMD in 18 patients, 8 for spinal disorders in 4 patients, and 5 for miscellaneous purposes in 4 patients. The CSF shunts were placed almost exclusively before 1990 and were associated with a significant number of complications. Patients undergoing CMD did very well, with only 1 patient failing to improve clinically. CONCLUSIONS: This review provides a historical perspective on the evolution of treatment of pediatric patients with achondroplasia. The use of CSF diversion procedures, formerly fraught with complications, is now rare following the realization of the natural history of CSF space enlargement in these patients. Cervicomedullary compression is more commonly recognized due to better imaging. Central apnea is now better detected by routine sleep studies. Spine surgery, although rare, requires evaluation of both spinal stenosis and instability. These patients are best evaluated by a multidisciplinary team.

High-grade primary diffuse leptomeningeal gliomatosis in a child with neurofibromatosis Type 1.

The authors report on a child with known neurofibromatosis Type 1 who developed high-grade diffuse leptomeningeal gliomatosis, without a known primary glioma. To the authors' knowledge, this is the first report of the coexistence of these conditions in a child.

AF6/s-afadin is a dual residency protein and localizes to a novel subnuclear compartment.

The AF6/afadin protein is a component of cell membranes at specialized sites of cell-cell contact. Two main splice variants exist, known as l- and s-afadin, respectively. L-afadin is widely expressed in cells of epithelial origin, whilst s-afadin expression is restricted to the brain. Here we demonstrate that the short form of AF6/s-afadin is a dual residency protein able to localize to the plasma membrane or nucleus whilst the long form of AF6, l-afadin is unable to localize to the nucleus. AF6/s-afadin clusters in a distinctive speckled pattern in the nucleus, but is unable to do so when cell cycle progression is inhibited at the G(1)/S or G(2)/M checkpoints. The formation of AF6/s-afadin nuclear bodies is also sensitive to the transcriptional activity of the cell with inhibition of RNA polymerase activity abolishing AF6/s-afadin nuclear clustering. AF6/s-afadin nuclear bodies localize to a novel subnuclear compartment, failing to colocalize with other known nuclear bodies. Formation of the AF6/s-afadin nuclear foci can be regulated by specific growth factor receptor mediated signaling events and by cytoplasmic tyrosine kinases, but does not correlate with tyrosine phosphorylation of AF6/s-afadin. AF6/s-afadin is a candidate for mediating control of cellular growth processes by regulated translocation to the nucleus.

Eve-3: a liver enriched suppressor of Ras/MAPK signaling.

BACKGROUND/AIMS: The developed liver is able to tightly control cellular proliferation, rapidly switching from quiescence to growth in response to specific stimuli. This suggests that growth inhibitors may be involved in the control of liver growth. We analyzed the role of the Spred-family of growth inhibitors in the liver. METHODS: We screened human EST databases for Spred-related sequences. Clones were isolated, sequenced, epitope-tagged and expressed. Subcellular localization of clones were determined and their effects on cellular signaling pathways analysed using specific antibodies. Cell cycle progression assays and protein interaction studies were initiated. Organ distribution of transcripts and their expression throughout liver development and in primary hepatocytes were recorded. RESULTS: We have identified a new, liver-restricted protein, Eve-3, containing a single Ena Vasp homology (EVH1) domain that can potently block activation of the Ras/MAPK pathway. Eve-3 is specific in inhibiting the Ras/MAPK pathway. Eve-3 can block serum-mediated cell cycle progression and its expression is highly regulated during liver development. CONCLUSIONS: The liver is the only organ that can regulate its growth and mass. Eve-3 may act as an inhibitor of proliferation pathways in the mature liver and be involved in modulating the unique regenerative capacity of this organ.

Distinct requirements for the Sprouty domain for functional activity of Spred proteins.

Sprouty and Spred {Sprouty-related EVH1 [Ena/VASP (vasodilator-stimulated phosphoprotein) homology 1] domain} proteins have been identified as antagonists of growth factor signalling pathways. We show here that Spred-1 and Spred-2 appear to have distinct mechanisms whereby they induce their effects, as the Sprouty domain of Spred-1 is not required to block MAPK (mitogen-activated protein kinase) activation, while that of Spred-2 is required. Similarly, deletion of the C-terminal Sprouty domain of Spred-1 does not affect cell-cycle progression of G(0)-synchronized cells through to S-phase following growth factor stimulation, while the Sprouty domain is required for Spred-2 function. We also demonstrate that the inhibitory function of Spred proteins is restricted to the Ras/MAPK pathway, that tyrosine phosphorylation is not required for this function, and that the Sprouty domain mediates heterodimer formation of Spred proteins. Growth-factor-mediated activation of the small GTPases, Ras and Rap1, was able to be regulated by Spred-1 and Spred-2, without affecting receptor activation. Taken together, these results highlight the potential for different functional roles of the Sprouty domain within the Spred family of proteins, suggesting that Spred proteins may use different mechanisms to induce inhibition of the MAPK pathway.

Overexpression of hyaluronan synthase-2 reduces the tumorigenic potential of glioma cells lacking hyaluronidase activity.

OBJECTIVE: The interactions of CD44 with hyaluronan are thought to be crucial for tumor cell attachment to the extracellular matrix, migration, and invasion. For migration to occur, however, the interactions between hyaluronan and cell surface receptors need to be transient. Hyaluronidases may facilitate the degradation of hyaluronan bound to the cell surface and thus reduce the interactions of the cells with the matrix, whereas the overproduction of hyaluronan in the absence of hyaluronidase activity may prevent cells from proliferating or invading normal surrounding tissue. METHODS: We analyzed the effects in vitro and in vivo of hyaluronan synthase-2 (HAS2) overexpression on a murine glioma cell line that is deficient in hyaluronidase activity. In addition, we evaluated the expression levels of HAS and hyaluronidase genes in human glioma cell lines and in glioma specimens. RESULTS: Increased hyaluronan synthesis had no effect on the in vitro proliferation of the cells but diminished their in vivo growth rate. Several human glioma cell lines were found to overexpress hyaluronan synthases, but they did so in conjunction with hyaluronidase Hyal2 and MGEA5 expression. Similarly, all glioblastomas multiforme expressed hyaluronidases MGEA5 and Hyal2. CONCLUSION: The data suggest that an increased synthesis of hyaluronan by astrocytoma cells is only promoting tumor cell growth in vivo if the cells express hyaluronidases as well.