Hyperplasia of Arachnoid Trabecular Cells: A Hitherto Undescribed Lesion Observed in the Setting of Neurofibromatosis Type 1.

Central nervous system manifestations, a variety of benign and malignant tumors as well as non-neoplastic abnormalities, are found in over 70% of neurofibromatosis type 1 (NF1) patients. Herein, we report hitherto undescribed space-occupying lesions in the setting of NF1. We aimed to clarify their characteristics, especially whether they represent neoplastic or non-neoplastic (hyperplastic) lesions. All 3 cases were preoperatively assessed as non-neoplastic; 2 and 1 cases were suspected to be arachnoid cysts and dilation of subarachnoid space, respectively. However, all lesions were revealed to be whitish jelly-like masses by operation, and the histology composed of spindle cells resembling arachnoid trabecular cells with moderate cellularity and cellular uniformity gave an impression that these lesions may be neoplastic. In contrast, electron microscopic analysis showed that the characteristics of these cells were compatible with those of normal arachnoid trabecular cells. Furthermore, whole-exome sequencing and array comparative genomic hybridization did not show any obvious alterations suggestive of their neoplastic nature. DNA methylation analysis demonstrated that these lesions were epigenetically distinct not only from meningiomas but also from normal healthy meninges. In conclusion, considering the clinicopathologic aspects of the present lesions and the results of the molecular analysis that failed to suggest their neoplastic nature, they may represent previously unrecognized rare hyperplasia of arachnoid trabecular cells, which may be associated with NF1.

Fatal Fungal Aneurysm Rupture Due to Aspergillosis after Craniopharyngioma Removal via Endoscopic Endonasal Surgery: Case Report and Comparison with Seven Reported Patients.

There has been a noted increase in the incidence of intracranial aspergillosis; this is often attributed to the wider use of antibiotics, corticosteroids, and immunosuppressants. Fungal cerebral aneurysms due to aspergillosis after neurosurgery remain extremely rare; in fact, only seven cases have been reported in the literature. In this study, we present a patient with an Aspergillus aneurysm that elicited subarachnoid hemorrhage after endoscopic endonasal surgery (EES) for craniopharyngioma. A 70-year-old woman with recurrent craniopharyngioma and steroid treatment underwent uneventful EES. On the 5th postoperative day, she suffered subarachnoid hemorrhage. As per her computed tomography angiography findings, an aneurysm was detected on the left internal carotid artery (ICA). Subsequent digital subtraction angiography showed occlusion of the ICA and an irregularly shaped wall. The diagnosis was pseudoaneurysm. We then performed craniotomy to place a left high-flow bypass and to trap the pseudoaneurysm. Despite continuous intensive care, she died on the 25th postoperative day of a huge, left cerebral infarct. The final diagnosis was made at autopsy; it revealed destruction of the ICA and Aspergillus invasion of the vessel wall, confirming the presence of a true fungal aneurysm. Perioperatively, patients with potential immunosuppression must be carefully managed. Advanced age is a risk factor. As surgery via the paranasal sinuses raises the risk for aspergillosis, fungal infection must be ruled out in patients whose postoperative course is deemed concerning.

Effect of Compound Muscle Action Potential After Peripheral Nerve Stimulation Normalization on Anesthetic Fade of Intraoperative Transcranial Motor-Evoked Potential.

PURPOSE: Anesthetic fade refers to the time-dependent decrease in the amplitude of the intraoperative motor-evoked potential. It is thought to be caused by the accumulation of propofol. The authors examined whether normalization by the compound muscle action potential (CMAP) after peripheral nerve stimulation could compensate for anesthetic fade. METHODS: In 1,842 muscles in 578 surgeries, which did not exhibit a motor-neurologic change after the operation, the motor-evoked potential amplitude was normalized by the CMAP amplitude after peripheral nerve stimulation, and the CMAP amplitude and operation times were analyzed. RESULTS: The amplitudes of both motor-evoked potential and CMAP increased over time after peripheral nerve stimulation because of the disappearance of muscle-relaxant action. Especially, after peripheral nerve stimulation, CMAP significantly increased from the beginning to the end of the operation. Anesthetic fade in transcranial motor-evoked potential monitoring seemed to occur at more than 235 minutes of surgery based on the results of a receiver operating characteristic analysis of the operation time and relative amplitudes. Although the mean amplitude without CMAP normalization at more than 235 minutes was significantly lower than that at less than 235 minutes, the mean amplitude with normalization by CMAP after peripheral nerve stimulation at more than 235 minutes was not significantly different from that at less than 235 minutes. CONCLUSIONS: Compound muscle action potential after peripheral nerve stimulation normalization was able to avoid the effect of anesthetic fade. Anesthetic fade was seemed to be caused by a decrease in synaptic transmission at the neuromuscular junction because of propofol accumulation by this result.

[False Aneurysm Formation at the Origin of the M2 Segment of the Middle Cerebral Artery Following a Blunt Head Trauma:A Case Report].

A 43-year-old man fell from a 1m-high truck loading platform and sustained an injury in the occiput. On admission, he was alert and neurologically intact. Computed tomography(CT)showed hemorrhage in the right sylvian fissure and parenchyma adjacent to the sphenoid wing. Magnetic resonance angiography detected no abnormalities. The course was uneventful for 11 days. However, on the 12th day, he spontaneously manifested with stupor. CT and CT angiography revealed expansion of the hemorrhage and an aneurysm arising from the origin of the M2 segment of the right middle cerebral artery. After superficial temporal artery to middle cerebral artery bypass, the aneurysm, a reddish pulsatile mass, was removed from the origin of the torn M2 segment, and the laceration was sutured. The histological diagnosis was false aneurysm. He recovered and was discharged 4 months after the trauma. Traumatic cerebral aneurysms are rare in the proximal segment of the middle cerebral artery. However, they should be distinguished from nontraumatic true aneurysms in the same region and treated as false aneurysms, which are major and critical traumatic aneurysms, for favorable outcomes.

Idiopathic spinal cord herniation: consideration of its pathogenesis based on the histopathology of the dura mater.

INTRODUCTION: We present a patient with idiopathic spinal cord herniation (ISCH) whose dura mater was histopathologically examined to elucidate its pathogenesis. CASE REPORT: A 33-year-old previously healthy man presented with progressive walking difficulty, spasticity of the right lower leg, and hyperesthesia below the right chest. Neuroimaging revealed right ventral displacement of the spinal cord at T5-6. The diagnosis was ISCH and he underwent release of the herniation from the ventral dural opening. Dural biopsy at the edge of the ventral opening and in the dorsal durotomy was performed. Postoperatively, his gait was improved. Histopathological examination of the ventral dural specimen showed non-specific degeneration, i.e., loose arrangements of collagen fibers, edematous changes, minor inflammatory cell infiltration, and angiogenesis. The specimen from the dorsal durotomy was normal. CONCLUSION: It is unclear whether the observed degeneration besides the ventral opening was the primary cause of ISCH or reflected secondary changes resulting from cumulative damage due to pulsation of the herniated spinal cord. However, the degeneration limited to the ventral opening suggests that ISCH was a local event in an individual with a normal dural theca.

Cutoff Points, Sensitivities, and Specificities of Intraoperative Motor-Evoked Potential Monitoring Determined Using Receiver Operating Characteristic Analysis.

BACKGROUND: Although intraoperative motor-evoked potential (MEP) monitoring is widely performed during neurosurgical operations, evaluating its results is controversial. STUDY AIMS: The cutoff point of MEP monitoring should be determined not only to predict but also to prevent postoperative neurologic deficits. MATERIAL AND METHODS: MEP monitoring was performed during 484 neurosurgical operations for patients without definitive preoperative motor palsy including 325 spinal operations, 102 cerebral aneurysmal operations, and 57 brain tumor operations, all monitored by transcranial stimulation, and 34 brain tumor operations monitored under direct cortical stimulation. To exclude the effects of muscle relaxants on MEP, the compound muscle action potential (CMAP), measured immediately after transcranial stimulation or direct cortical stimulation at supramaximal stimulation of the peripheral nerve, was used for normalization. The cutoff points, sensitivity, and specificity of MEP recorded during neurosurgery were examined by receiver operating characteristic (ROC) analyses and categorized according to the type of operation and stimulation. RESULTS: In spinal operations under transcranial stimulation, amplitude reduction of 77.9% and 80.6% as cutoff points for motor palsy with and without CMAP normalization, respectively, provided a sensitivity of 100% and specificity of 96.8% and 96.5%. In aneurysmal operations under transcranial stimulation, cutoff points of 70.7% and 69.6% offered specificities of 95.2% and 95.7% with and without CMAP normalization, respectively. The sensitivities for both were 100%. In brain tumor operations under direct stimulation, cutoff points were 83.5% and 86.3% with or without CMAP normalization, respectively, and the sensitivity and specificity for both were 100%. CONCLUSION: An amplitude decrease of 80% in brain tumor operations, 75% in spinal operations, and 70% in aneurysmal operations should be used as the cutoff points.

[Formation of a Subcutaneous Amputation Neuroma after Incomplete Endoscopic Carpal Tunnel Release Resulting in Complex Regional Pain Syndrome:A Case Report].

This 64-year-old woman had undergone endoscopic carpal tunnel release(ECTR)for right carpal tunnel syndrome 16 months earlier. Thereafter, she reported persistent dysesthesia in the thumb and index finger, developed burning pain in the middle and ring finger, paleness, coldness, and edema of the hand, a decreased range in hand motion, and a painful subcutaneous nodule just distal to the portal in the forearm. Based on physical, radiological, and electrophysiological studies, the diagnosis was incomplete carpal tunnel release associated with complex regional pain syndrome(CRPS). At open revision surgery, the carpal tunnel was released completely and the nodule was removed. Symptoms other than hypesthesia in the middle and ring fingers improved. Pathologically, the nodule was an amputation neuroma. Her CRPS was attributed to ECTR complications; i.e., persistence of median nerve compression and the formation of an amputation neuroma in the palmar cutaneous branch of the ulnar nerve at the portal. Surgeons must be aware that ECTR, a less invasive technique, may result in serious complications including CRPS.

MyD88 Mutation in Elderly Predicts Poor Prognosis in Primary Central Nervous System Lymphoma: Multi-Institutional Analysis.

BACKGROUND: Recent genetic analysis of primary central nervous system lymphoma (PCNSL) showed that the MyD88 L265P mutation, which is related to NF-κB signaling, was a genetic hallmark for PCNSL; thus it could serve as a genetic marker for diagnosis and a potential target for molecular therapy. However, the role of the MyD88 mutation in PCNSL has not been defined. In this study, we investigated the role of the MyD88 mutation and clinical features of PCNSL-treated patients at several institutions to determine its significance as a prognostic factor. METHODS: Forty-one PCNSL (diffuse large B-cell type) patients from 8 institutions were included in this study. Their median age was 68 years; median follow-up was 26.7 months; median overall survival was 26.7 months; and their 1-year, 3-year, and 5-year survival rates were 75.6%, 58.5%, and 43.9%, respectively. Deoxyribonucleic acid was extracted from frozen tissue, and the MyD88 L265P mutation was evaluated by polymerase chain reaction and direct sequencing. RESULTS: The MyD88 L265P mutation was found in 61.0% (25/41) of cases. Kaplan-Meier analysis revealed that neither MyD88 L265P mutation nor age >65 years alone significantly predicted overall survival relative to MyD88 wild type and age <65. The MyD88 L265P mutation was predominantly present in patients aged >65 years. Among age >65 patients, the MyD88 L265P mutation portended a worse overall survival compared with the MyD88 wild type (11.5 vs. 56.2 months P < 0.04). CONCLUSION: The MyD88 L265P mutation predicted a poor prognosis in elderly PCNSL patients. A new tailor-made treatment strategy might be needed for these patients.

The Appropriate Surgical Approach to a Greater Petrosal Nerve Schwannoma in the Setting of Temporal Lobe Edema.

BACKGROUND: Facial nerve schwannomas are rare lesions that constitute only 0.8% of all intrapetrous mass lesions. The least frequent lesions are tumors originating in the greater petrosal nerve (GPN). We present a case of a GPN schwannoma with temporal lobe edema in which the patient was operated on using an extradural and intradural approach to prevent complications. CASE DESCRIPTION: A 66-year-old woman with vertigo and abnormal magnetic resonance imaging findings was referred to our department. Computed tomography scan revealed an isodense subtemporal mass with partial rim calcification and petrosal bone apex erosion. Magnetic resonance imaging confirmed a 22-mm left middle fossa lesion with heterogeneous enhancement and edema of the temporal lobe. A left temporal craniotomy to the middle fossa was performed. The initial extradural exploration revealed the tumor to be in the Glasscock triangle, mainly involving the location of the GPN. The tumor was removed through an intradural approach in piecemeal fashion. Finally, using an extradural and intradural middle fossa approach, the tumor was totally removed, leaving the capsule on the middle fossa floor with continuous facial nerve monitoring. The postoperative course was uneventful without complications of xerophthalmia and facial palsy. CONCLUSIONS: GPN schwannomas are very rare lesions. The extradural and intradural middle fossa approach was used to preserve the tumor capsule around the GPN. Using this technique, one can safely protect the geniculate ganglion and the GPN.

Modified One-piece Supraorbital Approach for Orbital Tumors: Widely Preserved Orbital Roof in a Self-fitting Flap.

Objectives The one-piece supraorbital approach is a rational approach for the removal of orbital tumors. However, cutting the roof through the orbit is often difficult. We modified the technique to facilitate the osteotomy and improve the cosmetic effect. Design Three burr holes are made: the first, the MacCarty keyhole (burr hole 1), exposes the anterior cranial fossa and orbit; the second is placed above the supraorbital nerve (burr hole 2); and the third on the superior temporal line. Through burr hole 2, a small hole is created on the roof, 10 mm in depth. Next the roof is rongeured through burr hole 1 toward the preexisting small hole. Seamless osteotomies using a diamond-coated threadwire saw and the preexisting four holes are performed. Lastly the flap is removed. On closure, sutures are passed through holes in the cuts made with the threadwire saw, and tied. Results We applied our technique to address orbital tumors in two adult patients. The osteotomies in the roof were easy, and most parts of the roof were repositioned. Conclusions Our modification results in orbital osteotomies with greater preservation of the roof. Because the self-fitting flap does not require the use of fixation devices, the reconstruction is cosmetically satisfactory.

Intraoperative monitoring during decompression of the spinal cord and spinal nerves using transcranial motor-evoked potentials: The law of twenty percent.

Motor-evoked potential (MEP) monitoring was performed during 196 consecutive spinal (79 cervical and 117 lumbar) surgeries for the decompression of compressive spinal and spinal nerve diseases. MEP monitoring in spinal surgery has been considered sensitive to predict postoperative neurological recovery. In this series, transcranial stimulation consisted of trains of five pulses at a constant voltage (200-600 V). For the normalization of MEP, we recorded compound muscle action potentials (CMAP) after peripheral nerve stimulation, usually on the median nerve at the wrist 2 seconds before or after each transcranial stimulation of the motor area, for all operations. The sensitivity and specificity of MEP monitoring was 100% and 97.4%, respectively, or 96.9% with or without CMAP compensation (if the threshold of postoperative motor palsy was defined as 20% relative amplitude rate [RAR]). The mean RAR after CMAP normalization, of the most affected muscle in the patient group with excellent postoperative results (recovery rate of a Japan Orthopedic Association score of more than 50%) was significantly higher than that in the other groups (p=0.0224). All patients with an amplitude increase rate (AIR) with CMAP normalization of more than 20% achieved neurological recovery postoperatively. Our results suggest that if the RAR is more than 20%, postoperative motor palsy can be avoided in spinal surgery. If the AIR with normalization by CMAP after peripheral nerve stimulation is more than 20%, neurological recovery can be expected in spinal surgery.

Selecting an appropriate surgical treatment instead of carotid artery stenting alone according to the patient's risk factors contributes to reduced perioperative complications in patients with internal carotid stenosis: a single institutional retrospective analysis.

This retrospective study was aimed to compare the perioperative complications for internal carotid artery stenosis (ICS) in a Japanese single institute between the use of carotid artery stenting (CAS) alone or the use of an appropriate individualized treatment method allowing either carotid endarterectomy (CEA) or CAS based on patient risk factors. Based on the policy at our hospital, only CAS was performed on patients (n = 33) between January 2005 and November 2009. From December 2009 to December 2012, either CEA or CAS (tailored treatment) was selected for patients (n = 61) based on individual patient risk factors. CEA was considered the first-line treatment in all cases. In high-risk CEA cases, CAS was performed instead (n = 11), whereas in low-risk CEA cases, CEA was performed (n = 19). Further, in moderate-risk CEA cases based on own criteria, CAS was considered first, whereas for high-risk CAS cases, CEA was performed (n = 17). For low-risk CAS cases, CAS was performed (n = 9). Perioperative clinical complications (any stroke, myocardial infarction, or death within 30 days) were compared between both periods. Significantly reduced perioperative complications were observed during the tailored period (4/61 sites, 6.6%) as compared with the CAS period (8/33 sites, 24.2%) [Fisher's exact test p = 0.022; odds ratio, 4.56 (CAS/tailored); 95% confidence interval, 1.26-16.5]. Selecting an appropriate individualized treatment method according to patient risk factors, as opposed to adhering to a single treatment approach such as CAS, may contribute to improved overall outcomes in patients with ICS.

A case of atypical teratoid/rhabdoid tumor in the internal auditory canal.

OBJECTIVE: The case of a thirteen-year-old woman showing an atypical teratoid/rhabdoid tumor (AT/RT) primarily occurred in the internal auditory canal was presented. RESULTS: There was a delay in diagnosing AT/RT because of the first histological diagnosis of benign neurofibroma. If we had changed the surgical approach to one which was middle cranial fossa-based or translabyrinthine in the second or third operation, we might have reached an earlier final diagnosis. Although we faced a dilemma about whether to sacrifice facial nerve function for dissection of the tumor, we should have considered the possibility of malignancy at an earlier stage. CONCLUSION: This is a case report of AT/RT in the internal auditory canal presenting with progressive hearing loss as the initial symptom. Although no previous reports of AT/RT primarily occurring in the internal auditory canal are existent, this rare form of the disease should be considered in future evaluations as a differential diagnosis for internal auditory canal tumor.

[Differentiation between a thoracic spinal intramedullary lipoma and an intramedulary hematoma on fast spin-echo MRI scans: a case report].

We describe differentiation of a spinal intramedullary lipoma from an intramedullary hematoma on magnetic resonance images (MRI) with fast spin-echo (FSE) sequences. A 60-year-old man with dysesthesia in the legs and gait disturbance, was suspected of having myelopathy at a middle thoracic lesion. MRI with FSE sequences revealed an intramedullary lesion at T7 to T8. On the basis of hyperintensity on both T1-and T2-weighted images and a perilesional hypointense rim on T2-weighted images we made a diagnosis of subacute hematoma and planned observation. However, computed tomography for associated vertebral degeneration revealed a hypodense area (-97 Hounsfield units) in the region corresponding to the lesion depicted by MRI. We revised our diagnosis to an intramedullary lipoma and debulked the lesion. The lipoma was surrounded by a thick whitish capsule. Histopathologically, the capsule contained mature fat tissue and abundant collagen. The initial diagnosis was mainly attributable to specific FSE characteristics, i. e., the depiction of fat tissue as hyperintense on both T1-and T2-weighted images. Conventional spin-echo MRI depicts fat tissue as hyperintense on T1-and as hypointense on T2-weighted images. Other factors contributing to our initial diagnosis were MRI findings suggestive of an intramedullary hematoma, i. e., the intrinsic location of the lesion and the perilesional hypointense rim on T2-weighted images ascribable to collagen present in the capsule. The accurate diagnosis of an intramedullary lipoma on FSE requires correct interpretation of the signal, which is different from the signal on conventional spin-echo MRI.

Is the absolute value of O(6)-methylguanine-DNA methyltransferase gene messenger RNA a prognostic factor, and does it predict the results of treatment of glioblastoma with temozolomide?

OBJECTIVES: Methylation of O(6)-methylguanine-DNA methyltransferase (MGMT) has been reported to be a good prognostic factor for patients with glioblastoma multiforme (GBM). To determine whether the absolute value of MGMT messenger RNA (mRNA) might be a prognostic factor and useful for predicting the therapeutic effectiveness of temozolomide, especially with regard to GBMs, the authors measured the absolute value of MGMT mRNA in gliomas by using real-time reverse-transcription polymerase chain reaction (RT-PCR). METHODS: MGMT mRNA was measured in 140 newly diagnosed gliomas by real-time RT-PCR using the Taq-Man probe. Among 73 GBMs, 45 had been initially treated with temozolomide and radiation. RESULTS: The mean MGMT mRNA value was significantly lower in oligodendroglial tumors than in other tumors. In the 73 GBMs, a significant prognostic factor for progression-free survival was fewer than 1000 copies/ µgRNA of MGMT mRNA (p = 0.0150). Of 45 patients with GBMs that had been treated with temozolomide and radiation, progression-free survival was significantly longer for those whose GMB had fewer than 1000 copies/µgRNA of MGMT mRNA than for those whose GBM had more than 1000 copies/µgRNA (p = 0.0090). In 32 patients with GBMs treated by temozolomide and radiation whose age was younger than 75 years and whose Karnofsky Performance Scale score was more than 70, progression-free and overall survival times were longer for those with GBMs of fewer than 5000 copies/µgRNA of MGMT mRNA than for those with GBMs of more than 5000 copies/µgRNA (p = 0.0365 and p = 0.0312). CONCLUSIONS: MGMT mRNA might be useful as a prognostic factor and for predicting the results of therapy for GBMs treated by temozolomide. New individual adjuvant therapy based on the results of MGMT mRNA quantitation has been proposed.

Impact of platelet transfusion on survival of patients with intracerebral hemorrhage after administration of anti-platelet agents at a tertiary emergency center.

This study examined the impact of platelet transfusion (PLT) on the survival of intracerebral hemorrhage (ICH) patients who had been administered anti-platelet agents (APA). This retrospective cohort analysis investigated 432 patients (259 men, 60%) who were newly diagnosed with ICH between January 2006 and June 2011 at the tertiary emergency center of Kitasato University Hospital. Median age on arrival was 67.0 years (range, 40-95 years). ICH was subcortical in 72 patients (16.7%), supratentorial in 233 (53.9%), and infratentorial in 133 (30.8%). PLT was performed in 16 patients (3.7%). Within 90 days after admission to the center, 178 patients (41.2%) had died due to ICH. Before the onset of ICH, 66 patients had been prescribed APA because of atherosclerotic diseases. Multivariate regression analysis indicated APA administration was an independent risk factor for death within 7 days (odds ratio, 5.12; P = 0.006) and within 90 days (hazard ratio, 1.87; P = 0.006) after arrival. Regarding the effect of a PLT in ICH patients with APA, no patient with PLT died. PLT had a survival benefit on patients with ICH, according to our analysis. Further prospective analysis is necessary to confirm the effects of PLT on survival in ICH with APA.

Sacral myolipoma with symptomatic contraction of the conus at standing on tiptoe.

INTRODUCTION: We present a case with spinal myolipoma that was unique in its anatomical composition and symptomatology. CASE REPORT: An 18-year-old male presented with urinary retention and buttock pain exacerbated by standing on tiptoe underwent untethering of the low-set conus associated with a sacral fatty tract. Electrical stimulation of the spinal roots beside the upper conus induced anomalous caudal movement of the conus and contraction of the gastrocnemius muscle. In the lower conus, an ectopic muscle bridging the conus and dura was found, and the tissue contracted upon electrical stimulation. The histopathological diagnosis was myolipoma involving mature striated muscle and fat cells. Postoperatively his buttock pain was relieved immediately, but urinary retention persisted. CONCLUSION: We posit that his buttock pain, exacerbated by standing on tiptoe, was due to traction of the conus by contraction of the ectopic muscle that was aberrantly innervated from the sacral spinal roots.