Exertional Vertebrobasilar Insufficiency 6 Years after Vertebral Artery Dissection Treated with Occipital Artery-posterior Inferior Cerebellar Artery Anastomosis.

Exertional vertebrobasilar insufficiency (VBI) secondary to the non-atherosclerotic cause is uncommon. We herein report the case of a patient who developed exertional VBI long after extracranial right vertebral artery (VA) dissection. At the time of dissection, the right VA was completely occluded near its origin, but the distal flow was compensated by the collateral flow from the right deep cervical artery (DCA). After conservative management, the patient was discharged without neurologic deficit. Six years later, he developed recurrent VBI in association with the exertion of his right shoulder. A vascular evaluation revealed that the right proximal VA was still occluded, and there was no evidence of right subclavian artery lesions. The intracranial right VA flow was markedly reduced during the period, while branches of the right DCA were given off to the muscles of the right shoulder and neck. Then, occipital artery (OA)-posterior inferior cerebellar artery (PICA) anastomosis was performed. Intraoperative indocyanine green videoangiography (ICG) confirmed that the flow of the right PICA was predominantly supplied from the compensatory flow from the contralateral VA, and the antegrade flow in the right VA was clearly delayed in comparison to that of the left VA while there were prominent branches providing the blood flow to the medulla oblongata. After the anastomosis, these medullary branches provided the blood flow to the medulla oblongata more quickly and extensively than before. Postoperatively, VBI no longer occurred even after exertion. Surgical revascularization can be a viable option in the treatment of refractory VBI of the non-atherosclerotic cause.

Secondary INI1-deficient rhabdoid tumors of the central nervous system: analysis of four cases and literature review.

Atypical teratoid/rhabdoid tumors (AT/RT) are rare, highly malignant neoplasms of the central nervous system that predominantly occur in infants, and are characterized by the presence of rhabdoid cells and inactivation of INI1 or (extremely rarely) BRG1. The vast majority of AT/RT are recognized as primary tumors; however, rare AT/RT or INI1-deficient RT arising from other primary tumors have been reported. To better characterize secondary RT, we performed a histological and molecular analysis of four RT arising from pleomorphic xanthoastrocytoma (PXA), anaplastic PXA, low-grade astrocytoma, or ependymoma. Histologically, although conventional AT/RT are usually not largely composed of rhabdoid cells, three secondary RT were composed mainly of rhabdoid cells, two of which arising from (anaplastic) PXA exhibited marked nuclear pleomorphism reminiscent of that in the precursor lesions. Regarding INI1 alterations, although mutations including small indels are frequent in conventional AT/RT, only in one secondary RT had a mutation. Moreover, together with previously reported cases, biallelic INI1 inactivation in secondary RT was mostly due to biallelic focal and/or broad deletions. Although conventional AT/RT have stable chromosomal profiles, i.e., the frequency of copy number changes involving chromosomes other than chromosome 22 is remarkably low, our array comparative genomic hybridization analysis revealed numerous copy number changes in the secondary RT. In conclusion, secondary RT of the central nervous system are clinicopathologically and molecularly different from conventional pediatric AT/RT, and a nosological issue is whether these secondary RT should be called secondary "AT/RT" as most of the reported cases were.

Mechanical thrombectomy utilising a collateral pathway in a patient with dysgenesis of the internal carotid artery.

We describe a case of acute middle cerebral artery occlusion in a patient with ipsilateral internal carotid artery dysgenesis successfully treated with mechanical thrombectomy utilising a collateral pathway. During the procedure, a triaxial system using a balloon guiding catheter, flexible large lumen aspiration catheter and stent retriever was advanced from the left vertebral artery to the occluded left middle cerebral artery through the left posterior communicating artery. Because proximal aspiration from the balloon guiding catheter alone might have insufficient suction force due to the retrograde blood flow from large vascular communications (e.g. vertebral artery union), the tip of the flexible large lumen aspiration catheter was set at the proximal left middle cerebral artery, and distal aspiration was added during stent retrieval. A thrombolysis in cerebral infarction 2b result was achieved after the first pass. In this case, identification of carotid canal hypoplasia on computed tomography allowed for an immediate attempt of this alternative approach, avoiding a delay in the time to reperfusion.

Atypical Teratoid/Rhabdoid Tumor (AT/RT) Arising From Ependymoma: A Type of AT/RT Secondarily Developing From Other Primary Central Nervous System Tumors.

Atypical teratoid/rhabdoid tumors (AT/RT) are rare, aggressive, embryonal brain tumors that occur most frequently in very young children; they are characterized by rhabdoid cells and loss of INI1 protein nuclear expression. Here, we report the case of a 24-year-old man with a left frontal lobe tumor that was composed mainly of rhabdoid cells showing loss of INI1 nuclear reactivity and polyphenotypic immunohistochemical expression, with a small INI1-positive component of ependymoma. Array comparative genomic hybridization separately conducted for each histologically distinct component revealed 22 shared identical copy number alterations, including loss of heterozygosity of chromosome 22q containing the INI1 locus. Furthermore, we found the C11orf95-RELA fusion gene, the genetic hallmark of supratentorial ependymomas, not only in the ependymoma component but also in the AT/RT component by fluorescence in situ hybridization analysis, suggesting that the AT/RT cells secondarily progressed from the preexisting ependymoma cells. A second genetic inactivating event in the INI1 gene was not detected in the AT/RT component. There are several reported cases of AT/RT (or INI1-negative rhabdoid tumors) arising in the setting of other primary brain tumors (gangliogliomas, pleomorphic xanthoastrocytomas, and high-grade gliomas), but the present case

3D-CT Epidurography Can Detect Cerebrospinal-Fluid Leakage in a Patient with Spontaneous Intracranial Hypotension: A Case Report.

Spontaneous intracranial hypotension presents with many symptoms including orthostatic headache, dizziness, and nausea due to cerebrospinal-fluid (CSF) leakage from the spinal dural sac. Although CSF leakage can be estimated by radioisotope (RI) cisternography or computed tomography/magnetic resonance imaging myelography, it is not easy to detect the leakage point using these modalities. Here, we describe a patient with spontaneous intracranial hypotension in whom three-dimensional computed tomography (3D-CT) performed just after an epidural blood patch (EBP) containing contrast medium detected leakage point. The contrast medium injected into the epidural space at the L3/4 level migrated into the intradural space at the lower cervical spine level. RI cisternography performed before EBP did not show the CSF leakage point or any intracranial extension of the tracer. The rostral extension of the RI may be blocked by the collapse of the CSF space due to a large amount of CSF leakage, and due to the compression of the intradural CSF space by epidural CSF. 3D-CT epidurography may be useful to detect the fistula of a CSF leakage even in patients where other modalities including MRI, CT, or RI cisternography cannot specify the leakage point.

Acute Korsakoff syndrome following mammillothalamic tract infarction.

There are limited case reports of structural lesions causing Korsakoff syndrome. This report describes acute Korsakoff syndrome following localized, bilateral infarction of the mammillothalamic tracts (MTTs). Axial T2-weighted imaging revealed the lesions at the lateral wall level of the third ventricle and diffusion-weighted imaging confirmed that the left lesion was new and the right old. Korsakoff syndrome persisted 6 months after the onset. This case suggests that bilateral MTT dysfunction can lead to Korsakoff syndrome.

[Complications and diagnostic yield of stereotactic biopsy for the patients with malignant brain tumors].

PURPOSE: The purpose of this study was to assess the complication risk rate and diagnostic yield in a series of 211 procedures performed by a consistent method at one institute. MATERIAL AND METHOD: Two hundred and one patients underwent 211 stereotactic biopsy procedures for diagnosis of malignant brain tumor at Niigata University between 1987-2001. Indication for stereotactic biopsy is decided on the following factors: 1) the patient is elderly or unsuitable for craniotomy; 2) the tumor location is in a deep, diffusing, multiple, eloquent site; 3) cytoreductive surgery is not needed to treat the suspected pathology. The specimen was obtained from the target point of CT scan by the aspiration method under local anesthesia except for in six patients who were children or needed operation for a VP shunt under general anesthesia. The lesion was located in 114 cases of cerebral hemisphere, in 44 cases of basal ganglia, in 11 cases of cerebellum and in 11 cases of spreading site. RESULT: Histological diagnosis was obtained in 188 of 211 procedures and the diagnostic yield was 93.5%. There were 104 high grade gliomas, 16 low grade gliomas, 5 germ cell tumors, 37 malignant lymphomas, 19 metastatic tumors and 13 negative/inconclusive biopsies. Sixteen patients incurred complications (7.6%). Four patients (1.6%) suffered intratumoral hemorrhage. Emergency craniotomy was performed in three patients and stereotactic aspiration of hematoma was carried out in one patient. Furthermore, of 12 complications, 9 occurred with the patient showing symptoms of worsening neurological deficit, 2 occurred with general convulsion and 1 occurred with severe facial pain. CONCLUSION: This study provided evidence that stereotactic biopsy was a safe and reliable tool for patients with unresectable malignant brain tumors.