[A Case of a Solitary Plasmacytoma Extending into the Extradural Space].

Plasmacytomas are characterized by a monoclonal proliferation of plasma cells, and constitute the bulk of multiple myeloma. A solitary plasmacytoma is a rare entity, and is even more unlikely to occur intracranially. Here we present a 62-year-old man with an intracranial tumor. Magnetic resonance imaging revealed a large mass on the surface of the right fronto-parieto-temporal region, with extradurally directed growth. The tumor was enhanced homogenously by gadolinium, with dural tail-like findings, which resembled a meningioma. Head computed tomography scan showed osteolytic changes of the calvarium. Tumor removal following intravascular embolization was performed. The tumor seemed to have developed from the dura mater because it was firmly adhered to the dura but not to the calvarium. Histopathological analysis revealed monoclonal proliferation of plasma cells, which were positive for CD56, CD138, and lambda chain, on immunostaining. Since a systemic examination showed no evidence of other lesions, we diagnosed the tumor as a solitary dural plasmacytoma. There was no recurrence after postoperative radiotherapy. Rare entities, such as a solitary plasmacytoma, should be considered when an intracranial lesion with atypical radiological features is observed. If the lesion is anatomically resectable, histopathological evaluation is essential.

[A Case of Bilateral Traumatic Carotid-Cavernous Fistula].

Bilateral traumatic carotid-cavernous fistula(CCF)is rare. It is most commonly caused by a direct head or face injury involving the cavernous sinus and develops immediately after trauma. We report a case of bilateral traumatic CCF that occurred as an intracerebral hematoma(ICH)mimicking apoplexy 5 months later. We treated the patient with point occlusion of venous reflux causing an ICH using coil embolization to remove the hematoma. Three days after we performed trans-venous occlusion of the intercavernous connection and right cavernous sinus using coil embolization through the right inferior petrosal vein, it was identified that the left CCF was occluded after first embolization into the left sylvian vein. The mechanism of delayed development of traumatic CCF and spontaneous disappearance of CCF after occlusion of venous reflux are discussed.

Repression of wall shear stress inside cerebral aneurysm at bifurcation of anterior cerebral artery by stents.

The effect of a simple bare metal stent on repression of wall shear stress inside a model cerebral aneurysm was experimentally investigated by two-dimensional particle image velocimetry in vitro. The flow model simulated a cerebral aneurysm induced at the apex of bifurcation between the anterior cerebral artery and the anterior communicating artery. Wall shear stress was investigated using both stented and non-stented models to assess the simple stent characteristics. The flow behavior inside the stented aneurysm sac was unusual and wall shear stress was much smaller inside the aneurysm sac. Stent placement effectively repressed the temporal and spatial variations and the magnitude of wall shear stress. Hence, there is an effective possibility that would retard the progress of cerebral aneurysms by even simple stent.

[A synovial cyst accompanied by asymptomatic lumbar vertebral fracture requiring differentiation from spinal metastasis].

We experienced a case with a synovial cyst accompanied by asymptomatic lumbar vertebral fracture that required differentiation from spinal metastasis. An 82-year-old man suffered from right leg and anal pain. Computed tomography (CT) showed L5 spondylolysis. Magnetic resonance images (MRI) revealed an intra spinal cyst and acute lumbar vertebral fracture of L5 vertebral body. The surrounding area of the cyst presented contrast enhancement, and the extradural mass compressed the dural sac. Bone scintigraphy with 99m technetium-MDP demonstrated intense uptake on the right first, fourth, fifth, and seventh ribs and L2, L3, and L5 vertebra. The F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) image demonstrated an increased radiotracer uptake in the L5 vertebra(standardized uptake value(SUV) max=3.5). Spinal metastasis was suspected. Because of the cauda equina compression syndrome, it was surgically removed. Intraoperatively, a well-demarcated extradural cyst was found and compressed the dural sac markedly. The cyst capsule was thin and contained clear, thin fluid with no signs of bleeding. The histological diagnosis was a synovial cyst. His neurological symptoms improved after the surgery. The synovial cyst may enlarge after asymptomatic vertebral fractures.

Solitonic Windkessel Model for Intracranial Aneurysm.

The Windkessel model, which is known as a successful model for explaining the hemodynamic circulation, is a mathematical model with a direct correspondence with the electric circuit. We propose a theoretical model for the intracranial aneurysm based on the Windkessel-type steady blood flow. Intracranial aneurysms are well known vascular lesions, which cause subarachnoid hemorrhages. Since an aneurysm is an end-sack formed on the blood vessel, it functions as an unusual blood path that has characteristic features such as a reservoir and bottle neck orifice. We simulate an aneurysm by an electric circuit consisting of three different impedances, resistance, capacitance and inductance. A dumbbell-shaped aneurysm is the most dangerous aneurysm to easily rupture. Our aneurysmal model is created as a two-story aneurysm model for this point, thus namely the five-element Windkessel. Then, the mathematical formula was solved in numerical simulations by changing the size of the aneurysm and the elasticity of the aneurysm wall. An analysis of this model provided that the presence of the daughter aneurysm and the thinning of the aneurysm wall are positively correlated with a sharp increase in blood pressure in the aneurysm dome. Our mathematic aneurysm model proposes a good analogue to the real aneurysm and proved that this model includes soliton that is a non-decreasing wave propagation.

[Hypertrophic pachymeningitis associated with autoimmune pancreatitis examined for IgG4 related disease: a case report].

Hypertrophic pachymeningitis is a rare disease, and the fibrosing inflammatory process causes a thickening of the dura mater. A 62-year-old male undergoing corticosteroid therapy for autoimmune pancreatitis presented with headache and right facial numbness. Brain CT and MRI revealed thickened mass lesion around the tentorium. The specimen obtained by biopsy showed a small number of immunostain areas positive for IgG and IgG4. Systemic IgG4 related disease entity is proposed and analyzed from Japan, and pachymeningitis is also included in the examination. Some autoimmune mechanism is related to pachymeningitis, however, it is necessary to consider well if only the IgG4 has responsibility for the disease.

[Radiation-induced fibrosarcomas rapidly appeared more than 20 years after radiation therapy for germ cell tumors: report of two cases].

Radiation-induced brain tumor is a rare but serious and potentially fatal complication. We report two cases of radiation-induced fibrosarcomas which occurred more than 20 years after whole brain radiation therapy (60 Gy) for intracranial germinomas. Although both of them underwent imaging examination every year, the symptomatic sarcomas developed rapidly within a year. Eight months after total removal, the tumor recurred in the one case. Second surgery and gamma knife surgery could not prevent the tumor progression. In the other case, tumor regrowth was not observed during the five months follow-up after total removal surgery. It is important to keep in mind the possibility of a postradiation sarcoma that might have developed very aggressively after a long latent period.

Basilar artery trunk saccular aneurysms: morphological characteristics and management.

The purpose of this retrospective study was to report the morphological characteristics and results of surgical and endovascular treatment of basilar artery (BA) trunk saccular aneurysms. Twenty-two patients with 22 BA trunk saccular aneurysms underwent surgery including endovascular intervention. In this series, BA trunk aneurysms showed characteristic features such as so-called lateral aneurysm (41%), multiple aneurysms (32%), including two de novo aneurysms, and various vascular anomalies. Eleven craniotomies for neck clipping were performed for 11 ruptured aneurysms. However, in one of these cases, we abandoned neck clipping, because of concern for neck tearing, and embolized it later. Five ruptured and five unruptured aneurysms were successfully treated by endovascular surgery. Another one incompletely embolized aneurysm had grown to a huge size, and the patient underwent a Hunterian ligation with a flow reconstruction. The unusually high incidence of various associated vascular anomalies suggests that focal wall weakness must be based on the mechanism of aneurysm initiation. Most patients presented with subarachnoid hemorrhage. The pretreatment neurological state was predictive for clinical outcome. And, clinical outcomes in this series were not affected by the choice of treatment. However, considering that three of 11 surgical cases needed subsequent treatment, endovascular surgery should be considered as a first choice.

RNA sequencing analysis revealed the induction of CCL3 expression in human intracranial aneurysms.

Intracranial aneurysm (IA) is a socially important disease as a major cause of subarachnoid hemorrhage. Recent experimental studies mainly using animal models have revealed a crucial role of macrophage-mediated chronic inflammatory responses in its pathogenesis. However, as findings from comprehensive analysis of unruptured human IAs are limited, factors regulating progression and rupture of IAs in humans remain unclear. Using surgically dissected human unruptured IA lesions and control arterial walls, gene expression profiles were obtained by RNA sequence analysis. RNA sequencing analysis was done with read count about 60~100 million which yielded 6~10 billion bases per sample. 79 over-expressed and 329 under-expressed genes in IA lesions were identified. Through Gene Ontology analysis, 'chemokine activity', 'defense response' and 'extracellular region' were picked up as over-represented terms which included CCL3 and CCL4 in common. Among these genes, quantitative RT-PCR analysis using another set of samples reproduced the above result. Finally, increase of CCL3 protein compared with that in control arterial walls was clarified in IA lesions. Findings of the present study again highlight importance of macrophage recruitment via CCL3 in the pathogenesis of IA progression.

Individual adjuvant therapy for malignant gliomas based on O6-methylguanine-DNA methyltransferase messenger RNA quantitation by real-time reverse-transcription polymerase chain-reaction.

A new adjuvant therapy, individual adjuvant therapy (IAT), which is individualized according to the results of real-time reverse-transcription polymerase chain-reaction (RT-PCR) for O6-methylguanine-DNA methyltransferase (MGMT), was used to treat malignant gliomas. Immediately after the operation, mRNA expression for drug-resistance genes was investigated in frozen samples of malignant gliomas from 55 patients (30 glioblastoma multiformes, 20 anaplastic astrocytomas and 5 anaplastic oligodendroglial tumors) by real-time quantitative RT-PCR with specific primers for MGMT. Forty-two patients were treated with 1-(4-amino-2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU)-based chemotherapies since the relative quantitation value (RQV) of MGMT in real-time RT-PCR with SYBR-Green I was <1.0 or the absolute value of MGMT mRNA as measured by Taq Man probe methods normalized to the level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was <6.0x10(3) copies/microg RNA. Thirteen patients, whose tumors had an RQV of >1.0 or who had an absolute value of MGMT of >6.0x10(3) copies/microg RNA, were treated by platinum-based chemotherapy using cisplatin or carboplatin. The response rate was 40.9% for glioblastoma multiformes, 60.0% for anaplastic astrocytomas and 80.0% for anaplastic oligodendroglial tumors. The median survival period of 30 patients with glioblastoma treated by IAT was 21.7 months. The 2-year survival rate of glioblastoma patients treated by IAT was 70.9%. Our IAT, based on the results of real-time RT-PCR, may lead to a beneficial glioma therapy.

Motor evoked potential mapping and monitoring by direct brainstem stimulation. Technical note.

Motor evoked potentials (MEPs) by direct brainstem stimulation were generated during 12 neurosurgical operations performed in five posterior fossa tumors, six vertebrobasilar aneurysms, and an arachnoid cyst. The anterior aspect of the brainstem was exposed using a subtemporal approach (in six cases), a presigmoid approach (one case), or a lateral suboccipital approach (five cases). A train of five monopolar 5 to 25 mA pulses was then applied, and MEPs were recorded from the extremities. Motor evoked potentials were recorded in all patients (four mappings and seven monitorings) except in a 12-year-old child who underwent surgery for a posterior cerebral artery aneurysm. Although he experienced postoperative motor palsy, the aneurysm ruptured before electrodes could be placed. Two patients with postoperative motor palsy, one with a clival meningioma and one with a basilar trunk aneurysm, had shown significant decreases in MEP amplitude and even complete disappearance of MEPs during intraoperative brainstem stimulation. Motor evoked potentials elicited by direct brainstem stimulation seem to be an accurate neurophysiological monitoring method during operations around the anterior and lateral aspects of the brainstem.

Management and prognosis of cysts developed on long-term follow-up after Gamma Knife radiosurgery for intracranial arteriovenous malformations.

BACKGROUND: Delayed cyst formation is a well-recognized complication after radiosurgery for intracranial AVM. The objective of the present study was the evaluation of the different management options for these lesions and the corresponding prognosis of patients. METHODS: Between 2000 and 2005, 12 patients with intracranial AVM initially treated by GKR were reevaluated at Tokyo Women's Medical University because of delayed cyst formation in the vicinity of the target area. There were 7 men and 5 women. The mean age of the patients was 31.8 years at the time of GKR and 41.1 years at the time of complication. The average period between treatment and diagnosis of the complication constituted 6.7 years. All AVMs had lobar location and showed complete angiographic obliteration after GKR. RESULTS: The most common neurological signs and symptoms at the time of cyst presentation were headache (10 cases) and seizures (4 cases). Two patients were asymptomatic. Three patients underwent surgery soon after the diagnosis of the cyst, whereas initial observation was done in another 9. Among the latter, 5 patients had to be treated surgically thereafter because of persistent or aggravated neurological symptoms associated with radiological cyst expansion. Four other patients, including both asymptomatic ones, are in stable condition without surgery. Follow-up after treatment of the cyst varied from 7 to 60 months (average, 34.3 months). All patients are in good condition. CONCLUSIONS: Although delayed formation of cysts after GKR for intracranial AVM should be considered as a complication of the radiosurgical treatment, it has a relatively good prognosis. Observation can be recommended as initial option for compensated and asymptomatic patients.

Application of Ion-beam Implanted Expanded Polytetrafluoroethylene to Microvascular Decompression and the Surgical Outcome.

Accurate and long-term transposition of offending vessels is required in microvascular decompression (MVD) for the treatment of hemifacial spasm (HFS) and trigeminal neuralgia (TN). We created ion-beam implanted of an expanded-polytetrafluoroethylene (i-ePTFE) surface to transpose offending vessels in MVD. In 13 patients with MVD, we concealed and transposed offending vessels with tape-shaped i-ePTFE, and relieved facial and trigeminal nerve compression by attaching the i-ePTFE to the dura with fibrin glue. After surgery, none of the patients reported further symptoms or experienced recurrence of symptoms up to 12 months post-surgery. Favorable surgical outcomes are obtainable, since i-ePTFE has high tissue affinity and is easy to manipulate, even under a narrow and deep operative field. Our results suggested that i-ePTFE is very useful for transposition in MVD.

Rheological analyses of coagulation of blood from different individuals with special reference to procoagulant activity of erythrocytes.

In our previous papers, we reported that factor IX (FIX), when activated by erythrocyte membranes, causes coagulation. We have identified and characterized the FIX-activating enzyme located in normal human erythrocyte membranes. In this paper, to examine physiological and pathological significances of procoagulant activity of erythrocytes, coagulation of blood obtained from different individuals was analyzed by means of a rheological technique. In more than 65% of subjects including normals and patients, the initiation of coagulation seemed to be governed by erythrocytes. Coagulation of whole blood and platelet-free plasma supplemented with erythrocytes had a tendency to occur rapidly in the elderly. It was suggested that the concentration of FIX-activating enzyme on erythrocyte membranes for aged donors was somewhat higher than that for young ages. Propagation reactions on erythrocyte membranes (i.e. factor X activation leading to thrombin generation after FIX activation) was slower than that on platelet membranes. Moreover, the propagation reaction on erythrocyte membranes was greatly dependent on individuals, whereas that on platelet membranes was not so much. Our study demonstrates that the activation of FIX by erythrocytes and subsequent propagation reaction on platelet membranes may be important for initiating and controlling blood coagulation reactions.

Brain metastasis from a lung mucoepidermoid carcinoma mimicking a brain abscess.

BACKGROUND: Mucoepidermoid carcinoma (MEC) is a rare tumor of the lung that accounts for 0.1-0.2% of all pulmonary tumors. To the best of our knowledge, brain metastasis from lung MEC is rare and magnetic resonance imaging (MRI) findings of this lesion have not been documented. CASE DESCRIPTION: We herein report the case of a 72-year-old male. MRI revealed a left parietal tumor showing ring enhancement with medium gadolinium contrast and an evident high intensity area in the nonenhanced central portion on diffusion-weighted images (DWI) mimicking a brain abscess. Histologically, MEC is composed of a mixture of different cell types including mucin-secreting glandular cells and squamous cells. Accordingly, we suggest that the high DWI signal can be explained by the development of intracellular and intraluminal mucin, which have a high viscosity. CONCLUSION: Further accumulation of cases with brain metastasis from MEC is needed to establish the characteristic image findings, which would lead to prompt and adequate treatment.

Essential role of Gap junctions in NO- and prostanoid-independent relaxations evoked by acetylcholine in rabbit intracerebral arteries.

BACKGROUND AND PURPOSE: Direct intercellular communication via gap junctions may play a central role in endothelium-dependent relaxations that are mediated by a conducted hyperpolarization and do not involve the synthesis of NO and prostanoids. In the present study, inhibitory peptides homologous to the Gap27 domain of the second extracellular loop of connexin37/connexin43 and connexin40, designated as 37,43Gap27 and 40Gap27, respectively, were used to evaluate the role of this mechanism in intracerebral arteries. METHODS: Isolated rings of rabbit middle cerebral artery were constricted by histamine (10 micromol/L) in the presence of N(G)-nitro-L-arginine methyl ester (300 micromol/L) and indomethacin (10 micromol/L). Concentration-relaxation curves for acetylcholine were constructed in the presence and absence of 37,43Gap27 and 40Gap27. Specific antibodies were used to delineate the distribution of connexin37, connexin40, connexin43, and connexin45 within the arterial wall. RESULTS: Individually, 37,43Gap27 and 40Gap27 minimally affected endothelium-dependent relaxations to acetylcholine at concentrations of 300 micro mol/L, whereas their combination (at 300 micromol/L each) inhibited the maximal response by approximately 70% and increased the EC50 value for relaxation by approximately 15-fold. In endothelium-denuded rings, this peptide combination did not attenuate responses to sodium nitroprusside, an exogenous source of NO. Gap junction plaques, whose incidence was highest in endothelium, were constructed from connexin40 and connexin43 in the media and connexin37, connexin40, and connexin43 in the endothelium. CONCLUSIONS: The findings confirm that direct communication via gap junctions contributes to agonist-induced relaxations of intracerebral arteries. More than one connexin subtype appears to participate in such responses.

Continuous laryngoscopic vocal cord monitoring for vascular malformation surgery in the medulla oblongata: technical note.

OBJECTIVE: Resection of lesions located in the medulla oblongata may result in significant morbidity. The most lethal complications are swallowing disturbances, which can lead to aspiration pneumonia. To prevent this problem, the lower cranial nerves can be mapped with recording needles placed in the posterior pharyngeal wall and the tongue. However, mapping alone is not sufficient to preserve the lower cranial nerves and swallowing functions. To overcome this problem, we attempted to devise a method to intraoperatively monitor vocal cord movements with a laryngoscope. We used this method, in addition to other types of brainstem mapping, in three cases. METHODS: Recording needles were inserted into the posterior pharyngeal wall and the tongue, to record the responses of Cranial Nerves IX and XII. A laryngoscope was inserted orally, for direct observation of vocal cord movements, and was maintained until the end of the operation. The floor of the fourth ventricle was stimulated with a monopolar stimulator. Somatosensory evoked potentials, auditory evoked potentials, and motor evoked potentials were simultaneously monitored. RESULTS: We were able to confirm synchronized vocal cord adduction with stimulation of the expected vagal trigonum location and to monitor rhythmic vocal cord movements during spontaneous respiration. In all three cases, we removed the lesions without postoperative complications. CONCLUSION: In addition to intraoperative vocal cord monitoring with a laryngoscope, we could safely determine the optimal location for the first incision in the floor of the fourth ventricle. Potentially lethal postoperative complications can be avoided with brainstem mapping and vocal cord monitoring.

Optic nerve arteriovenous malformation causing optic apoplexy: case report.

OBJECTIVE AND IMPORTANCE: Vascular malformations in the optic pathway are rare. Only one case of pathologically confirmed arteriovenous malformation (AVM) of the optic nerve has been reported previously. We document the case of a patient with an optic nerve AVM who presented with optic apoplexy that was diagnosed with the use of magnetic resonance imaging. CLINICAL PRESENTATION: A 15-year-old girl developed left visual disturbance of sudden onset while playing badminton. A magnetic resonance imaging scan disclosed left optic nerve swelling and intraoptical hemorrhage, although an angiogram did not reveal abnormal vessels. INTERVENTION: The patient underwent total removal of the hematoma and tangles of the abnormal vessels in the left optic nerve, which was diagnosed pathologically as an AVM. The patient recovered visual acuity, but the left visual field defect remained unchanged. CONCLUSION: Along with cavernous malformations and optic gliomas, AVMs can be a rare cause of optic nerve apoplexy. T2-weighted magnetic resonance imaging is useful in rendering the diagnosis of an optic nerve AVM, observed as a mass lesion consisting of serpiginous, tangled, low-intensity bands. Early surgical treatment is recommended to obtain a rapid recovery.

Pathological findings of angiographically occult vascular malformation.

Forty cases with angiographically occult vascular malformations (AOVMs), in which the diagnosis was confirmed pathologically, are analysed. Pathology of the AOVMs were classified into 22 AVMs (20 thrombosed, two cryptic), 16 cavernous malformations and two capillary telangiectasias. The location of AOVMs were in the cerebral hemisphere (32), cerebellum (3), thalamus (2), lateral ventricle (1), brain stem (1) and optic nerve (1). Common characteristic histopathological features between thrombosed AVMs and cavernous malformations were that the malformations had subclinically bled in the past and apparently had proceeded to undergo various degree of thrombosis, fibrosis and calcification. However, in addition to these findings, the thrombosed AVMs showed a contribution of arterial components, hypertrophied vascular wall and intervening gliotic tissue. On the other hand, the cavernous malformations showed closely packed abnormal vessels with surrounding collagen band. All cryptic AVMs presented with haemorrhagic episodes and small nidus within clot were proven in histological specimens. Common histopathological findings between thrombosed AVMs and cavernous malformations are discussed.