Roberta Morace

KIAA1549-BRAF Fusions and IDH Mutations Can Coexist in Diffuse Gliomas of Adults

KIAA1549‐BRAF fusion gene and isocitrate dehydrogenase (IDH) mutations are considered two mutually exclusive genetic events in pilocytic astrocytomas and diffuse gliomas, respectively. We investigated the presence of the KIAA1549‐BRAF fusion gene in conjunction with IDH mutations and 1p/19q loss in 185 adult diffuse gliomas. Moreover BRAFv600E mutation was also screened. The KIAA1549‐BRAF fusion gene was evaluated by reverse‐transcription polymerase chain reaction (RT‐PCR) and sequencing. We found IDH mutations in 125 out 175 cases (71.4%). There were KIAA1549‐BRAF fusion gene in 17 out of 180 (9.4%) cases and BRAFv600E in 2 out of 133 (1.5%) cases. In 11 of these 17 cases, both IDH mutations and the KIAA1549‐BRAF fusion were present, as independent molecular events. Moreover, 6 of 17 cases showed co‐presence of 1p/19q loss, IDH mutations and KIAA1549‐BRAF fusion. Among the 17 cases with KIAA1549‐BRAF fusion gene 15 (88.2%) were oligodendroglial neoplasms. Similarly, the two cases with BRAFv600E mutation were both oligodendroglioma and one had IDH mutations and 1p/19q co‐deletion. Our results suggest that in a small fraction of diffuse gliomas, KIAA1549‐BRAF fusion gene and BRAFv600E mutation may be responsible for deregulation of the Ras‐RAF‐ERK signaling pathway. Such alterations are more frequent in oligodendroglial neoplasm and may be co‐present with IDH mutations and 1p/19q loss.

Stop-event-related potentials from intracranial electrodes reveal a key role of premotor and motor cortices in stopping ongoing movements

In humans, the ability to withhold manual motor responses seems to rely on a right-lateralized frontal–basal ganglia–thalamic network, including the pre-supplementary motor area and the inferior frontal gyrus (IFG). These areas should drive subthalamic nuclei to implement movement inhibition via the hyperdirect pathway. The output of this network is expected to influence those cortical areas underlying limb movement preparation and initiation, i.e., premotor (PMA) and primary motor (M1) cortices. Electroencephalographic (EEG) studies have shown an enhancement of the N200/P300 complex in the event-related potentials (ERPs) when a planned reaching movement is successfully stopped after the presentation of an infrequent stop-signal. PMA and M1 have been suggested as possible neural sources of this ERP complex but, due to the limited spatial resolution of scalp EEG, it is not yet clear which cortical areas contribute to its generation. To elucidate the role of motor cortices, we recorded epicortical ERPs from the lateral surface of the fronto-temporal lobes of five pharmacoresistant epileptic patients performing a reaching version of the countermanding task while undergoing presurgical monitoring. We consistently found a stereotyped ERP complex on a single-trial level when a movement was successfully cancelled. These ERPs were selectively expressed in M1, PMA, and Brodmanns area (BA) 9 and their onsets preceded the end of the stop process, suggesting a causal involvement in this executive function. Such ERPs also occurred in unsuccessful-stop (US) trials, that is, when subjects moved despite the occurrence of a stop-signal, mostly when they had long reaction times (RTs). These findings support the hypothesis that motor cortices are the final target of the inhibitory command elaborated by the frontal–basal ganglia–thalamic network.

Alpha, beta and gamma electrocorticographic rhythms in somatosensory, motor, premotor and prefrontal cortical areas differ in movement execution and observation in humans

OBJECTIVE In the present study, we tested the hypothesis that both movement execution and observation induce parallel modulations of alpha, beta, and gamma electrocorticographic (ECoG) rhythms in primary somatosensory (Brodmann area 1-2, BA1-2), primary motor (BA4), ventral premotor (BA6), and prefrontal (BA44 and BA45, part of putative human mirror neuron system underlying the understanding of actions of other people) areas. METHODS ECoG activity was recorded in drug-resistant epileptic patients during the execution of actions to reach and grasp common objects according to their affordances, as well as during the observation of the same actions performed by an experimenter. RESULTS Both action execution and observation induced a desynchronization of alpha and beta rhythms in BA1-2, BA4, BA6, BA44 and BA45, which was generally higher in amplitude during the former than the latter condition. Action execution also induced a major synchronization of gamma rhythms in BA4 and BA6, again more during the execution of an action than during its observation. CONCLUSION Human primary sensorimotor, premotor, and prefrontal areas do generate alpha, beta, and gamma rhythms and differently modulate them during action execution and observation. Gamma rhythms of motor areas are especially involved in action execution. SIGNIFICANCE Oscillatory activity of neural populations in sensorimotor, premotor and prefrontal (part of human mirror neuron system) areas represents and distinguishes own actions from those of other people. This methodological approach might be used for a neurophysiological diagnostic imaging of social cognition in epileptic patients.

A rapid and reliable procedure to localize subdural electrodes in presurgical evaluation of patients with drug-resistant focal epilepsy

OBJECTIVES To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning.

Extradural arteriovenous fistulas involving the vertebral artery in neurofibromatosis Type 1: Case report

Spinal extradural arteriovenous fistulas (AVFs) are rare lesions that may be associated with neurofibromatosis Type 1 (NF1). In these patients, the shunt typically occurs between the V(2) segment of the vertebral artery and the epidural venous plexus. Previously, reported cases have been treated either by using endovascular embolization or, sporadically, by open surgery. In surgical reports, proximal deafferentation or manipulation of the venous portion of the shunt--including suture, resection, or open embolization of the epidural ectasia--was attempted with variable results. The authors report on a case of a young patient with NF1 who underwent emergency surgical disconnection of a cervical extradural AVF after previously unsuccessful endovascular and surgical therapy. The lesion drained into a giant intrathecal varix, causing severe myelopathy. After surgery, the patient recovered almost completely. This experience clarified the surgical anatomy of these malformations and showed that, when surgery is necessary, the optimal treatment providing complete and permanent cure of this condition is direct closure of the epidural shunt pedicle.

Blockage of A2A and A3 adenosine receptors decreases the desensitization of human GABAA receptors microtransplanted to Xenopus oocytes

We previously found that the endogenous anticonvulsant adenosine, acting through A2A and A3 adenosine receptors (ARs), alters the stability of currents (IGABA) generated by GABAA receptors expressed in the epileptic human mesial temporal lobe (MTLE). Here we examined whether ARs alter the stability (desensitization) of IGABA expressed in focal cortical dysplasia (FCD) and in periglioma epileptic tissues. The experiments were performed with tissues from 23 patients, using voltage-clamp recordings in Xenopus oocytes microinjected with membranes isolated from human MTLE and FCD tissues or using patch-clamp recordings of pyramidal neurons in epileptic tissue slices. On repetitive activation, the epileptic GABAA receptors revealed instability, manifested by a large IGABA rundown, which in most of the oocytes (≈70%) was obviously impaired by the new A2A antagonists ANR82, ANR94, and ANR152. In most MTLE tissue-microtransplanted oocytes, a new A3 receptor antagonist (ANR235) significantly improved IGABA stability. Moreover, patch-clamped pyramidal neurons from human neocortical slices of periglioma epileptic tissues exhibited altered IGABA rundown on ANR94 treatment. Our findings indicate that antagonizing A2A and A3 receptors increases the IGABA stability in different epileptic tissues and suggest that adenosine derivatives may offer therapeutic opportunities in various forms of human epilepsy.

Intraoperative localization of subcortical brain lesions

SummaryBackground. Some brain tumors may grow immediately beneath the cortical surface without distorting its appearance. Intraoperative image guidance promotes safe resection. We have developed MRI-based corticotopography (MRI-bct), to localize lesions during surgery, using simple, non-dedicated equipment, to match a three-dimensional reconstruction with the corresponding appearance of the brain cortex. Methods. Forty-six patients underwent resection of subcortical brain lesions, aided by MRI-bct. The lesions had a maximum diameter less than 3 cm, were subcortical but no deeper than the floor of the nearest cerebral sulcus. Each patient had a volumetric MRI scan with and without contrast administration. Data sets were transferred to a laptop personal computer and processed using a rendering software. At operation, the three-dimensional model of the brain, including a surface overlay of the lesion, was matched to the exposed brain surface. After its exact relationship with the overlying sulcal pattern was defined, the lesion was localized and resected. In selected patients, the procedure was coupled with functional brain mapping. Results. Data processing took from 10 to 15 min and could be done whenever convenient before operation. Surface matching between the surgical field and the reformatted MRI always required less than 5 min and was done near the operating table. In all patients, the lesion was identified at the first attempt, through a small corticotomy, regardless of the brain shift after dural opening. Conclusions. MRI-bct is a practical, time-saving neuronavigational aid ideal for localizing superficial lesions underlying the cerebral cortex because it unmistakably characterizes the adjacent sulcal anatomy.

Intracranial Capillary Hemangioma: A Description of Four Cases

OBJECTIVE Capillary hemangiomas are benign vascular lesions involving the skin and soft tissues that commonly occur at birth or an early age. Intracranial capillary hemangiomas are extremely rare; only 14 cases have been reported the literature. CASE DESCRIPTION We describe four patients with capillary hemangiomas. In two of these patients the lesions arose from the cavernous sinus. In the third patient, a large capillary hemangioma arising from the middle cranial fossa extended into the infratemporal fossa. The fourth patient had a left hemorrhagic temporoparietal capillary hemangioma. RESULTS The first two patients underwent a partial resection, followed by radiotherapy. Local tumor control was achieved in both cases, as shown by the follow-up magnetic resonance imaging. In the third patient the lesion was subtotally removed after embolization. Radiotherapy, performed one year after surgery because of recurrence, allowed tumor control. In the fourth patient surgical removal was total and no adjuvant radiotherapy was required after surgery; follow-up magnetic resonance imaging did not show any recurrence at the one-year follow-up. CONCLUSION Surgery is an option for symptomatic intracranial capillary hemangiomas. However, because partial removal is associated with a high recurrence rate, capillary hemangiomas that cannot be removed radically should be treated with radiotherapy, which offers the possibility of controlling lesion size and preventing tumor recurrence.

Temporal pole abnormalities in temporal lobe epilepsy with hippocampal sclerosis: Clinical significance and seizure outcome after surgery

PURPOSE To assess the clinical significance of temporal pole abnormalities (temporopolar blurring, TB, and temporopolar atrophy, TA) in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS) with a long post-surgical follow-up. METHODS We studied 60 consecutive patients with TLE-HS and 1.5 preoperative MRI scans who underwent surgery and were followed up for at least 5 years (mean follow-up 7.3 years). Based on findings of pre-surgical MRI, patients were classified according to the presence of TB or TA. Groups were compared on demographic, clinical, neuropsychological data, and seizure outcome. RESULTS TB was found in 37 (62%) patients, while TA was found in 35 (58%) patients, always ipsilateral to HS, with a high degree of overlap (83%) between TB and TA (p<0.001). Patients with TB did not differ from those without TB with regard to history of febrile convulsions, GTCSs, age of epilepsy onset, side of surgery, seizure frequency, seizure outcome, and neuropsychological outcome. On the other hand, they were significantly older, had a longer duration of epilepsy, and displayed lower preoperative scores on several neuropsychological tests. Similar findings were observed for TA. Multivariate analysis corroborated the association between temporopolar abnormalities and age at onset, age at surgery (for TB only), and lower preoperative scores on some neuropsychological tests. CONCLUSIONS Temporopolar abnormalities are frequent in patients with TLE-HS. Our data support the hypothesis that TB and TA are caused by seizure-related damages. These abnormalities did not influence seizure outcome, even after a long-term post-surgical follow-up.

Absorbable intradermal closure of elective craniotomy wounds.

OBJECTIVE More and more commonly, craniotomies are being performed with minimal hair shaving to improve cosmesis and facilitate return to a normal life. In such patients, traditional sutures or metal staples are used for scalp closure. This practice requires suture removal, often perceived as a cause of discomfort by the patient. We investigate the safety and efficacy of intradermal sutures in a large, consecutive series of patients undergoing elective craniotomy. METHODS Wound healing complications were investigated in a consecutive series of 208 patients who underwent elective craniotomy during a 2-year period. In all patients, minimal shaving, performed by shaving a small strip of hair along the planned wound, was used. Scalp closure was achieved with only absorbable intradermal running sutures. All wounds were covered with sterile adhesive strips, which were kept in place for 24 hours postoperatively. Patients were followed for a mean follow-up period of 10.6 months (range, 1–23 mo). RESULTS All patients except two had satisfactory wound healing. One patient (0.48%) developed cerebrospinal fluid leakage, which responded to bed rest and lumbar drainage. Another patient (0.48%) had a superficial skin infection, which was successfully treated with topical wound care and oral antibiotics. CONCLUSION The closure method described is safe and effective. The absence of visible sutures in the postoperative course reinforces the cosmetic advantage of no shaving and decreases discomfort associated with the removal of sutures or staples.