Khaled M. Krisht

The pathogenetic features of cerebral cavernous malformations: a comprehensive review with therapeutic implications

Cerebral cavernous malformations (CCMs) are common vascular lesions of the CNS that may lead to seizures, focal neurological deficits, and fatal hemorrhagic stroke. Human genetic studies have identified 3 genes associated with CCM, and biochemical and molecular studies in mice have elucidated signaling pathways with important therapeutic implications. In this review, the authors shed light on the 3 discovered CCM genes as well as their protein products, with particular emphasis on their signal transduction pathways and their interaction with one another. Close focus is directed at mice model studies involving the Ccm2 gene product signaling pathway, revealing an important role for the use of simvastatin or other RhoA inhibitors as a therapeutic modality in the treatment of CCM. The remaining challenges to creating a more faithful CCM animal model as well as future clinical and research implications are reviewed.

Myxoid meningioma: a rare metaplastic meningioma variant in a patient presenting with intratumoral hemorrhage.

Myxoid (metaplastic) meningioma is a rare WHO Grade I meningioma subtype arising from the leptomeninges. It has unique Alcian blue stromal staining and distinctive cellular interdigitations, junctional complexes, and nucleolar pseudoinclusions on ultrastructural pathology that help to distinguish it from other meningioma variants. The authors describe the case of a rare left middle fossa, extraaxial myxoid meningioma in a 50-year-old woman to emphasize the important histological characteristics and observations essential for making a precise diagnosis. To their knowledge this is the seventh reported case of a myxoid meningioma in the literature and the sixth case in an adult; however, it is the first reported instance of myxoid meningioma in a patient presenting with intratumoral hemorrhage.

Sellar and parasellar metastatic tumors.

The sellar and parasellar (SPS) region is a complex area rich in vital neurovascular structures and as such may be the location of first manifestation of a systemic malignancy. Metastases to this region are rare; breast cancer is the most common source among those that metastasize to the SPS region. Ophthalmoplegia, headache, retroorbital or facial pain, diabetes insipidus, and visual field defects are the most commonly reported symptoms. Lack of specific clinical and radiological features renders SPS metastases difficult to differentiate from the other frequently encountered lesions in this area, especially when there is no known history of a primary disease. Currently accepted management is multimodality therapy that includes biopsy and/or palliative surgical resection, radiation, and chemotherapy. Although no significant survival benefits have been shown by the surgical series, surgical resection may improve quality of life. Here we review the relevant literature and present six illustrative cases from our own institution.

Extraspinal Type I Dural Arteriovenous Fistula with a Lumbosacral Lipomyelomeningocele: A Case Report and Review of the Literature

Seven cases of adult spinal vascular malformations presenting in conjunction with spinal dysraphism have been reported in the literature. Two of these involved male patients with a combined dural arteriovenous fistula (DAVF) and lipomyelomeningocele. The authors present the third case of a patient with an extraspinal DAVF and associated lipomyelomeningocele in a lumbosacral location. A 58-year-old woman with rapid decline in bilateral motor function 10 years after a prior L4-5 laminectomy and cord detethering for diagnosed tethered cord underwent magnetic resonance imaging showing evidence of persistent cord tethering and a lipomyelomeningocele. Diagnostic spinal angiogram showed a DAVF with arterial feeders from bilateral sacral and the right internal iliac arteries. The patient underwent Onyx embolization of both feeding right and left lateral sacral arteries. At 6-month follow-up, MRI revealed decreased flow voids and new collateralized supply to the DAVF. The patient underwent successful lipomyelomeningocele exploration, resection, AV fistula ligation, and cord detethering. This report discusses management of this patient as well as the importance of endovascular embolization followed by microsurgery for the treatment of cases with combined vascular and dysraphic anomalies.

Tanycytic ependymoma: a challenging histological diagnosis.

Tanycytic ependymoma is a rare form of ependymoma that usually arises in the intramedullary spine. It has a unique histology emphasized by the inconspicuous ependymal pattern of cells and close resemblance to schwannoma and astrocytoma. The authors report a 50-year-old man with a cervical tanycytic ependymoma that was initially thought to be a schwannoma. The frozen histology section showed spindle cells with oval and elongated nuclei with occasional hemosiderin deposits present suggesting a preliminary diagnosis of schwannoma. Immunohistochemical staining of the permanent section revealed strong immunoreactivity for glial fibrillary acidic protein with intermittent S-100 positivity, confirming that the tumor was a tanycytic ependymoma. This underlines the challenges involved in making an accurate diagnosis and demonstrates that careful and detailed histological inspection with immunohistochemical stains and ultrastructural microscopy may be necessary to distinguish tanycytic ependymoma from other neoplasms.

Subarachnoid Hemorrhage from a Thoracic Radicular Artery Pseudoaneurysm after Methamphetamine and Synthetic Cannabinoid Abuse: Case Report

Background Context Isolated spinal artery aneurysms not associated with vascular malformations are exceedingly rare. Purpose To present a rare case of subarachnoid hemorrhage after thoracic radiculomedullary artery pseudoaneurysm rupture in a patient who abused synthetic cannabinoids and methamphetamines. Study Design Case report. Methods A 41-year-old man with a history of polysubstance abuse presented with acute-onset headache, back pain, and transient bilateral lower-extremity numbness. He reported daily use of the synthetic cannabinoid “Spice.” He denied use of other illegal drugs, but laboratory testing was positive for methamphetamines. Magnetic resonance imaging showed a focal hematoma at T2–3, and spinal angiography was negative for vascular abnormalities; however, a follow-up angiogram 6 days later revealed interval development of an irregular dilation of the left T3 radiculomedullary artery originating from the left supreme intercostal artery. Results Surgical trapping and resection of the lesion yielded a good clinical outcome. Conclusions Although two previous case reports have described patients with thoracic radiculomedullary pseudoaneurysm causing spinal subarachnoid hemorrhage (SAH), this is the first reported case associated with synthetic cannabinoids and methamphetamine abuse. Although this diagnosis is exceptionally rare, clinical presentation of SAH with associated back pain and lower-extremity symptoms warrants an aggressive imaging workup. Even in the setting of negative angiography, repeat cerebral and spinal angiograms may be necessary to identify a potentially treatable cause of spinal SAH.

Management considerations and strategies to avoid complications associated with the thoracoscopic approach for corpectomy.

The thoracoscopic approach to the anterior spine is a practical and valuable means of approaching ventral spinal lesions but demands advanced technical skills and fine hand-eye coordination that is usually acquired with experience. A mutual understanding of all the ventilatory and surgical steps allows for an organized orchestration between the anesthesiologist and surgeon, which ultimately helps minimize potential complications. Despite a concerted effort by all involved to avoid risks, thoracoscopic surgery is associated with complications for which the surgical team should be cognizant. In this paper, the authors detail the operative technique of vertebral corpectomy and interbody fusion via the thoracoscopic approach for the treatment of ventral spinal pathology involving the thoracic and lower lumbar spine, discuss complications known to occur with the thoracoscopic approach, and present means to help avoid them.

Intraventricular Hemorrhage after Epidural Blood Patching: An Unusual Complication

The authors present two cases of intraventricular hemorrhage (IVH) believed to be a result of epidural blood patching. The first was a 71-year-old woman who had new onset of nontraumatic IVH on computed tomography (CT) scan after undergoing an epidural blood patch (EBP). This amount of intraventricular blood was deemed an incidental finding since it was of very small volume to account for her overall symptoms. The second patient, a 29-year-old woman, was found to have nontraumatic IVH three days after undergoing an EBP. This was seen on CT scan of the head for workup of pressure-like headaches, nausea, vomiting, and absence seizures. Conservative management was followed in both instances. Serial CT scan of the head in our first patient displayed complete resolution of her IVH. The second patient did not have follow-up CT scans because her overall clinical picture had improved significantly. This highlights a potential sequel of EBP that may be observed on CT scan of the head. In the event that IVH is detected, signs and symptoms of hydrocephalus should be closely monitored with the consideration for a future workup if warranted by the clinical picture.

Combined chronic lymphocytic leukemia and prolactinoma: a rare occurrence in a patient presenting with pituitary apoplexy.

The authors describe a rare case of combined pituitary chronic lymphocytic leukemia (CLL) and prolactinoma in a 77-year-old man presenting with apoplexy. This case highlights the importance of evaluating the pituitary gland in patients with CLL who present with clinical manifestations of apoplexy as well as the need to carefully evaluate pathological specimens from the gland for the presence of lymphocytic cells in those patients. This is the first reported case of a combined CLL-prolactinoma pituitary lesion presenting with apoplexy.

Giant Spontaneous Epidural Pneumatocele: Case Report and Review of the Literature

BACKGROUND Pneumocephalus is a commonly encountered finding in neurosurgery in which air displaces intracranial cerebrospinal fluid after cranial surgery or a cerebrospinal fluid leak into paranasal or mastoid sinuses. When an intracranial air collection becomes chronically established in a fixed loculation causing mass effect, pneumatocele is a more appropriate term. We present an unusual case of a spontaneous giant frontotemporal epidural pneumatocele that persisted for more than 1 year before the patient presented for neurological treatment. CASE DESCRIPTION A 40-year-old man with a remote history of minor head trauma presented with symptoms of headaches, dizziness, and vertigo. Imaging revealed a right giant epidural pneumocephalus secondary to bony dehiscence of the intracranial wall of the mastoid bone. A subtemporal middle fossa approach was performed to repair the mastoid defect with hydroxyapatite, fat graft, and temporalis fascia. The patient was discharged on postoperative day 2 with improvement in his headaches. One month after discharge operative imaging demonstrated complete resolution of his epidural pneumatocele and improvement in his headaches. CONCLUSIONS This unique case represents the first reported case in the neurosurgical literature of a giant spontaneous epidural pneumatocele occurring in an adult treated with a middle fossa approach with resolution on follow-up imaging.