Gene mutation profiling of primary glioblastoma through multiple tumor biopsy guided by 1H-magnetic resonance spectroscopy

Genetic mutation has served as the biomarkers for the diagnosis and treatment of glioblastoma multiforme (GBM). However, intra-tumor heterogeneity may interfere with personalized treatment strategies based on mutation analysis. This study aimed to characterize somatic mutation profiling of GBM. We collected 33 samples from 7 patients with the primary GBM associated with different Choline (Cho) to N-acetylaspartate (NAA) index (CNI) through the frameless proton magnetic resonance spectroscopy (1H-MRS) guided biopsies and investigated multiple somatic mutations profiling using the AmpliSeq cancer hotspot panel V2. We identified 53 missense or nonsense mutations in 27 genes including some novel mutations such as APC and IDH2. The mutations in EGFR, TP53, PTEN, PIK3CA genes were presented with different frequency and the majority of the mutated gene was only shared by 1-2 samples from one patient. Moreover, we found the association of CNI with histological grade, but there was no significant change of CNI in the presence of TP53, EGFR and PTEN mutations. These data suggest that gene mutations constitute a heterogeneous marker for primary GBM which may be independent of intra-tumor morphological phenotypes of GBM; therefore, gene mutation markers could not be determined from a small number of needle biopsies or only confined to the high-grade region.

Surgically treated incidentally discovered low-grade gliomas are mostly IDH mutated and 1p19q co-deleted with favorable prognosis

OBJECTIVE

LGGs (low-grade gliomas) are sometimes encountered by chance during radiological examinations. These incidentally discovered LGGs (IDLGGs) were relatively under-studied in the literature. The purpose of current study is to review a cohort of patients with IDLGGs surgically treated in our institution for their clinical and histological aspects and determine their IDH1 and 1p19q status.

METHODS

All patients with hemispheric LGGs receiving operation in our institution between 2001 and 2004 were reviewed. Clinical, radiological and treatment data of the patients were collected and IDLGGs were retrieved and compared with symptomatic LGGs. Histological review was carried out and formalin-fixed paraffin embedded (FFPE) tissues of IDLGGs were examined for IDH1/IDH2 mutation and 1p/19q codeletion.

RESULTS

Twenty three IDLGGs (10.4%) were identified while 196 patients had symptomatic LGGs. The reasons for patients with IDLGGs having radiological examination included trauma (47.8%), dizziness (26.1%), unrelated headache (21.7%), and health checkup (4.4%). Clinically, patients with IDLGGs had higher preoperative KPS (P < 0.001), smaller tumor volume (P = 0.014), lower frequency of eloquent areas involvement (P < 0.001) and higher rate of complete resection (P = 0.037) comparing to those with symptomatic LGGs. Histologically, there is a preponderance of oligodendroglial differentiation with 6 oligodendrogliomas and 11 oligoastrocytomas but there were also 6 astrocytomas. IDH1 mutation and 1p/19q co-deletion were detected in 95.7% (22/23) and 69.6% (16/23) of IDLGGs, respectively. The latter encompassed all but one of the cases of oligodendroglial tumors. Patients with IDLGGs had longer overall survival than those with symptomatic LGGs (P = 0.027).

CONCLUSIONS

We conclude that the majority of IDLGGs are IDH1 mutated and are predominantly oligodendroglial tumors. With a median follow-up of 9.3 years to our series, we conclude that patients with IDLGGs had better prognosis than those with symptomatic LGGs. The favorable prognosis of IDLGGs may be accounted by the higher practicability of extensive resection, non-eloquent tumor location and smaller tumor volume. Frequent IDH1 mutation and 1p/19q co-deletion in IDLGGs may also contribute to the favorable prognosis of this subgroup of patients.

Minimal invasive trans-eyelid approach to anterior and middle skull base meningioma: a preliminary study of Shanghai Huashan hospital

Transpalpebral or trans-eyelid approach is a modified trans-orbital access to lesions of anterior cranial fossa and sellar region. But whether this approach is also suitable for tumors extending laterally to the temporal lobe or middle cranial fossa is not clarified. We would like to share our experiences from the cadaveric anatomy study to clinical operations. We used 5 cadavers to study trans-eyelid approaches in a step-by-step fashion. And then assisted by an experienced ophthalmologist for incisions, we treated 3 female patients via this approach: One with spheno-orbital meningioma, one with sellar tuberculum meningioma, and the other with medial sphenoidal wing meningioma. After studying the cadavers, we made several revisions to the previously reported approach: 1) move the incision close to the edge of the eyelid, which resembled the double-eyelid incision. 2) A vascularized periosteum flap was dissected for repairing the opened frontal sinus and reconstruction of the skull base. 3) The dura was sutured up with a slice of temporalis muscle. Then we treated 3 patients by this approach. All tumors were totally resected as Simpson Grade I. Complications included orbital apex syndrome and transient oculomotor paralysis because of tumor invasion into orbit and cavernous sinus. No cerebrospinal fluid leakage. We find that trans-eyelid approach is suitable for lesions not only at anterior cranial base or sellar region, but also extending to middle cranial base, especially around sphenoidal wings within 2 cm range or spheno-orbital region. Thus, we propose whether it appropriate to nominate this approach as 'trans-eyelid pterional approach', since it may treat some anterior and middle cranial fossa lesions with a mini-craniotomy around pterion.

Medulloblastoma in China: clinicopathologic analyses of SHH, WNT, and non-SHH/WNT molecular subgroups reveal different therapeutic responses to adjuvant chemotherapy

Medulloblastoma (MB) is one of the most common primary central nervous system tumors in children. Data is lacking of a large cohort of medulloblastoma patients in China. Also, our knowledge on the sensitivity of different molecular subgroups of MB to adjuvant radiation therapy (RT) or chemotherapy (CHT) is still limited. The authors performed a retrospective study of 173 medulloblastoma patients treated at two institutions from 2002 to 2011. Formalin-fixed paraffin embedded (FFPE) tissues were available in all the cases and sections were stained to classify histological and molecular subgroups. Univariate and multivariate analyses were used to investigate prognostic factors. Of 173 patients, there were 118 children and 55 adults, 112 males and 61 females. Estimated 5-year overall survival (OS) rates for all patients, children and adults were 52%, 48% and 63%, respectively. After multivariate analysis, postoperative primary radiation therapy (RT) and chemotherapy (CHT) were revealed as favorable prognostic factors influencing OS and EFS. Postoperative primary chemotherapy (CHT) was found significantly improving the survival of children (p<0.001) while it was not a significant prognostic factor for adult patients. Moreover, patients in WNT subtype had better OS (p = 0.028) than others (SHH and Non-SHH/WNT subtypes) given postoperative adjuvant therapies. Postoperative primary RT was found to be a strong prognostic factor influencing the survival in all histological and molecular subgroups (p<0.001). Postoperative primary CHT was found significantly to influence the survival of classic medulloblastoma (CMB) (OS p<0.001, EFS p<0.001), SHH subgroup (OS p = 0.020, EFS p = 0.049) and WNT subgroup (OS p = 0.003, EFS p = 0.016) but not in desmoplastic/nodular medulloblastoma (DMB) (OS p = 0.361, EFS p = 0.834) and Non-SHH/WNT subgroup (OS p = 0.127, EFS p = 0.055). Our study showed postoperative primary CHT significantly influence the survival of CMB, SHH subgroup and WNT subgroup but not in DMB and Non-SHH/WNT subgroup of MB.

Risk factors for rebleeding of aneurysmal subarachnoid hemorrhage: a meta-analysis

Background

Rebleeding is a serious complication of aneurysmal subarachnoid hemorrhaging. To date, there are conflicting data regarding the factors contributing to rebleeding and their significance.

Methods

A systematic review of PubMed and Embase databases was conducted for studies pertaining to aneurysmal subarachnoid hemorrhage (aSAH) and rebleeding in order to assess the associated risk factors. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated from fourteen studies comprised of a total of 5693 patients that met the inclusion criteria.

Results

Higher rebleeding rates were observed < 6 h after the initial aSAH (OR  = 3.22, 95% CI  = 1.46–7.12), and were associated with high systolic blood pressure (OR  = 1.93, 95% CI  = 1.31–2.83), poor Hunt-Hess grade (III–IV) (OR  = 3.43, 95% CI  = 2.33–5.05), intracerebral or intraventricular hematomas (OR  = 1.65, 95% CI  = 1.33–2.05), posterior circulation aneurysms (OR  = 2.15, 95% CI  = 1.32–3.49), and aneurysms >10 mm in size (OR  = 1.70, 95% CI  = 1.35–2.14).

Conclusions

Aneurysmal rebleeding occurs more frequently within the first 6 hours after the initial aSAH. Risk factors associated with rebleeding include high systolic pressure, the presence of an intracerebral or intraventricular hematoma, poor Hunt-Hess grade (III-IV), aneurysms in the posterior circulation, and an aneurysm >10 mm in size.

Proteomic analysis of cerebrospinal fluid: toward the identification of biomarkers for gliomas

Gliomas are the most common primary brain tumors in adults and, despite advances in the understandings of glioma pathogenesis in the genetic era, they are still ineradicable, justifying the need to develop more reliable diagnostic and prognostic biomarkers for this malignancy. Because changes in cerebrospinal fluid (CSF) are suggested to be capable of sensitively reflecting pathological processes, e.g., neoplastic conditions, in the central nervous system, CSF has been deemed a valuable source for potential biomarkers screening in this era of proteomics. This systematic review focused on the proteomic analysis of glioma CSF that has been published to date and identified a total of 19 differentially expressed proteins. Further functional and protein-protein interaction assessments were performed by using Protein Analysis Through Evolutionary Relationships (PANTHER) website and Ingenuity Pathway Analysis (IPA) software, which revealed several important protein networks (e.g., IL-6/STAT-3) and four novel focus proteins (IL-6, galanin (GAL), HSPA5, and WNT4) that might be involved in glioma pathogenesis. The concentrations of these focus proteins were subsequently determined by enzyme-linked immunosorbent assay (ELISA) in an independent set of CSF and tumor cyst fluid (CF) samples. Specifically, glioblastoma (GBM) CF had significantly lower GAL, HSPA5, and WNT4 levels than CSF from different grades of glioma. In contrast, IL-6 level was significantly higher in GBM CF when compared with CSF and, among different CSF groups, was highest in GBM CSF. Therefore, these candidate protein biomarkers, identified from both the literatures and in silico analysis, may have potentials in clinical diagnosis, prognosis evaluation, treatment response monitoring, and novel therapeutic targets identification for patients with glioma.

Serological identification of URGCP as a potential biomarker for glioma

AIM

Glioblastoma multiforme (GBM) is one of the most frequent human brain tumor and causes dismal outcome. To identify tumor-associated antigens in GBM patients may find potential diagnostic markers and immunotherapeutic targets. In this study, we identified a gene termed URGCP using the serological identification of antigens by recombinant A2B5 positive glioma cDNA library. The gene product of URGCP is immunogenic in GBM after tested in allogenic patients serum screening.

METHODS AND RESULTS

GBM patients with an auto-antibody response against URGCP show longer survival than those without URGCP response. In additional, we show that URGCP was high expression in most GBM tissues and cell lines compared with normal brain tissues and majorly co-expressed with stem cell marker A2B5.

CONCLUSION

We identified a potential new biomarker of GBM, URGCP. The findings indicate that URGCP is immunogenic in human GBM and suggest its potential use as diagnostic and immunotherapeutic for GBM patients.

Lymphoplasmacyte-rich meningioma: our experience with 19 cases and a systematic literature review

OBJECTIVE

To investigate the clinicopathological characteristics, prognosis, pathology, and differential diagnosis of LPM by analyzing our experience and reviewed relevant literature. We also postulated the necessity of postoperative adjuvant therapy.

METHODS

19 patients with LPM underwent surgical treatment from 2007 through 2010 in our department. The clinical charts of the patients, including surgical, histological, and follow-up records, as well as imaging studies, were analyzed retrospectively. Other 43 cases searched from the literature were also included, so that 62 LPM cases were summarized and reviewed together.

RESULTS

The summarized 62 patients comprised 30 males and 31 females aged 9 years to 79 years (40.7±18.3 years). The most common locations were convexity, skull base, para-sagittal and cervical canal. Multiple or diffuse lesions were found in 8 cases. There were 13 patients had peripheral blood abnormalities (21%). One-third of the cases had moderate to severe peritumoral brain edema. Thirty-eight patients had total resection, 12 patients not specified while 12 received subtotal resection or only biopsy. MIB-1 was available in 24 cases and a third of them were higher than 3%. Follow-up more than 3 year was only completed in 19/62 cases. Seven cases suffered recurrence and two of them died after 2 years of operation.

CONCLUSION

LPM is a very rare benign variant of intracranial meningioma. Both lesions and hematological abnormalities have a predilection for younger individuals. Preoperative diagnosis of this subtype of meningioma is still difficult. Surgical resection is the primary treatment option, and supportive care for those not totally removed is very important, because the recurrence rate for this subtype is rather low. However, the massive infiltration of lymphocytes and plasma cells in LPMs are still controversial and the long-term follow-ups are needed. Radiotherapy is not recommended, and hormonal or immune-inhibitor therapy might be helpful.

Clinical application of motor pathway mapping using diffusion tensor imaging tractography and intraoperative direct subcortical stimulation in cerebral glioma surgery: a prospective cohort study

BACKGROUND

Glioma surgery in eloquent areas remains a challenge because of the risk of postoperative motor deficits.

OBJECTIVE

To prospectively evaluate the efficiency of using a combination of diffusion tensor imaging (DTI) tractography functional neuronavigation and direct subcortical stimulation (DsCS) to yield a maximally safe resection of cerebral glioma in eloquent areas.

METHODS

A prospective cohort study was conducted in 58 subjects with an initial diagnosis of primary cerebral glioma within or adjacent to the pyramidal tract (PT). The white matter beneath the resection cavity was stimulated along the PT, which was visualized with DTI tractography. The intercept between the PT border and DsCS site was measured. The sensitivity and specificity of DTI tractography for PT mapping were evaluated. The efficiency of the combined use of both techniques on motor function preservation was assessed.

RESULTS

Postoperative analysis showed gross total resection in 40 patients (69.0%). Seventeen patients (29.3%) experienced postoperative worsening; 1-month motor deficit was observed in 6 subjects (10.3%). DsCS verified a high concordance rate with DTI tractography for PT mapping. The sensitivity and specificity of DTI were 92.6% and 93.2%, respectively. The intercepts between positive DsCS sites and imaged PTs were 2.0 to 14.7 mm (5.2 ± 2.2 mm). The 6-month Karnofsky performance scale scores in 50 postoperative subjects were significantly increased compared with their preoperative scores.

CONCLUSION

DTI tractography is effective but not completely reliable in delineating the descending motor pathways. Integration of DTI and DsCS favors patient-specific surgery for cerebral glioma in eloquent areas.

The Stupp regimen preceded by early post-surgery temozolomide versus the Stupp regimen alone in the treatment of patients with newly diagnosed glioblastoma multiforme (GBM)

2022

Background: In treatment of newly diagnosed GBM with the Stupp chemo-radiotherapy regimen, following by adjuvant chemotherapy, patients were treated with temozolomide (TMZ) & combined radiotherapy 4-5 weeks after surgery. In the interval between surgery and chemo-radiotherapy, it is not known whether additional TMZ treatment will improve efficacy or safety. This trial evaluated the safety and efficacy of the Stupp regimen + early post-surgery TMZ chemotherapy in the treatment of patients with newly diagnosed GBM. Methods: The trial was a multi-center, randomized open-label study. 99 newly diagnosed GBM patients were enrolled and randomly assigned to the Stupp regimen + early post-surgery TMZ chemotherapy arm (experimental group, n = 52) or to Stupp regimen alone (control group, n = 47). Fourteen days after surgery, the patients in experiment group recieved TMZ orally at 75mg/m2/day for 14 days. The primary endpoint of the study was the overall survival (OS). The secondary endpoints included the progression-free survival (PFS), objective tumor assessment and adverse events (AEs). Results: The median OS time was 17.58 months (95% CI: 15.18 – 23.03 months) in the experiment group and 13.17 months (95% CI: 11.14 – 18.76 months) in the control group (log-rank test, p = 0.021). There is no significantly difference in the median PFS between experiment group and control group (8.74 months, 95% CI: 6.41-14.85 months vs 10.38 months, 95% CI: 8.18-15.44 months, p = 0.695). No statistically significant difference was detected as regards to the objective tumor assessments. There is no significance in OS or PFS between MGMT positive and MGMT negative groups. TMZ treatment was well tolerated in the study. AE types and rates were generally similar between the two groups. There were 22 SAEs in this study, with only 1 SAE (lung infection) in Stupp regimen group was possibly drug-related. Conclusions: The addition of early post-surgery TMZ chemotherapy to the Stupp regimen for newly diagnosed GBM resulted in a statistically significant survival benefit with minimal additional toxicity. Clinical trial information: NCT00686725.

Papillary meningioma: clinical and histopathological observations

Papillary meningioma is a rare subtype of malignant meningiomas, which is classified by the World Health Organization as Grade III. Because of lack of large sample size case studies, many of the specific characteristics of papillary meningioma are unclear. This study investigated by retrospective analysis the clinical, radiological and histopathological findings of 17 papillary meningioma patients who underwent surgical resection or biopsy, to assess the characteristics of papillary meningioma. Eight female and nine male patients were included, with a mean age of 40 (range: 6 to 55) years. Tumors were mostly located in the cerebral convexity and showed irregular margins, absence of a peritumoral rim, heterogeneous enhancement and severe peritumoral brain edema on preoperative images. Brain invasion was often confirmed during the operations, with abundant to exceedingly abundant blood supply. Intratumoral necrosis and mitosis was frequently observed on routinely stained sections. The average MIB-1 labeling index was 6.9%. Seven cases experienced tumor recurrence or progression, while seven patients died 6 to 29 months after operation. Radiation therapy was given in 52.9% of all cases. Univariate analysis showed that only the existence of intratumoral necrosis and incomplete resection correlated with tumor recurrence. The 3-year progression free survival was 66.7% after gross total resection and 63.6% for other cases. The 3-year mortality rate was 50% after gross total resection and 63.6% for other cases. Papillary meningioma has specific clinical and histopathological characteristics. Tumor recurrence (or progression) and mortality are common. Gross total tumor resection resulted in less recurrence and mortality.

Secretory meningiomas: clinical, radiological and pathological findings in 70 consecutive cases at one institution

Secretory meningioma (SM) is a rare, benign subtype of meningioma. Between January 2005 and December 2010, 70 SMs were operated on at the Department of Neurosurgery, Huashan Hospital, Fudan University. We retrospectively analyzed the clinical data, radiological and immunohistochemical findings, and patient outcome to discuss the specific features of SMs. Cranial base preference, hyper-signal in T2 weighted MR image, "xenon light" gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhancement were frequently observed in the 70 cases. Non-skull base SMs, which received more complete resection (p<0.01) and had better short-term and long-term outcome, were observed with more severe peritumoral brain edema (PTBE) (p<0.001). In follow-up, only 1 cranial base SM case showed tumor progression. 3 cases died after operation, all with cranial base SMs. As for the 10 cases given Simpson grade 3 or 4 resection who were available at follow-up, 3 died, 5 received gamma-knife therapy, and the other 2 cases received no treatment at all. Only one of the 2 residual SMs without postoperative radiation presented minor progression at a median of 48 months follow-up. In conclusion, cranial base preference, hyper-signal T2 weighted MR image and "xenon light" GD-DTPA enhancement are specific for SMs. Prognosis of SMs is related with operation completeness and surgical risks, rather than the extent of PTBE. Residual SM grows slowly and reacts well to gamma-knife therapy.

Clinical features of intracranial vestibular schwannomas

The aim of the present study was to discuss the clinical features of intracranial vestibular schwannomas and to evaluate the symptoms and signs as well as their correlation with tumor extension. The records of 1,009 patients who were treated in Shanghai Huashan Hospital were reviewed retrospectively. According to the Samii classification of 1997, the patients were grouped into a T3 and a T4 group based on the radiological findings. We focused our analysis on the incidence of subjective disturbances versus objective morbidity, and symptomatology versus tumor size and extension. Of the 1,009 cases, 424 patients (42.0%) were defined as T3 while 585 patients (58%) were defined as T4. The most frequent clinical symptoms were hearing loss (85.8%), facial numbness (48.9%), ataxia (44.6%), tinnitus (40.1%), deafness (26.3%) and facial paralysis (21.1%). The ratios of gender, vertigo and facial paralysis were significantly different between the T3 and T4 groups (P<0.05); however, none of the clinical symptoms had a positive likelihood ratio (PLR) greater than 10 for T4 prediction. The most frequent cranial nerve disturbance was associated with the cochlear nerve (92.6%) and trigeminal nerve (53.5%). Disturbance of the facial nerve was more severe in T3 than T4 patients (P<0.05). Hearing deficit, facial paresthesia, ataxia and tinnitus are key symptoms of huge vestibular schwannomas. Cochlear, trigeminal and facial nerves were the most commonly affected cranial nerves in cases of large tumors. Gender and tumor size were associated with tumor extension. Although the predictive value was limited, the symptoms of vertigo, facial paralysis and hearing loss may be indicators of tumor growth.

Thymic stromal lymphopoietin: a promising therapeutic target for allergic diseases

Thymic stromal lymphopoietin (TSLP), an interleukin 7-like cytokine, can trigger dendritic cell (DC)-mediated T-helper type 2 (Th2) inflammatory responses. Recent evidence demonstrates that cytokines TSLP and OX40 (CD134)/OX40 ligand seem to be important players in the maintenance of Th2 memory pool in the pathogenesis of asthma. Accumulating data reveal that the pathogenic T cells involved in asthma are likely to be inflammatory Th2 cells. TSLP is involved in the development of asthma through crosstalk with nuclear factor NF-ĸB. Progression of skin fibrosis in atopic dermatitis occurs via TSLP/TSLP receptor. TSLP-mediated dermal inflammation aggravates experimental allergic asthma. Also, TSLP polymorphisms are associated with susceptibility to asthma, atopic dermatitis, and eczema herpeticum. These findings suggest a master switch of TSLP in the initiation of allergic and adaptive inflammation through innate pathways at the epithelial cell-DC interface. The TSLP pathway is therefore a promising target for immunotherapy of allergic diseases.

Preoperative surgical planning for intracranial meningioma resection by virtual reality

BACKGROUND

The Dextroscope system by Volume Interactions (Singapore) had been applied to minimally invasive neurosurgery in many units. This system enables the neurosurgeon to interact intuitively with the three-dimensional graphics in a direct manner resembling the way one communicates with the real objects. In the paper, we explored its values in pre-operation surgical planning for intracranial meningiomas resection.

METHODS

Brain computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance venography (MRV) were performed on 10 patients with parasagittal and falcine meningiomas located on central groove area; brain CT, MRI and magnetic resonance angiography (MRA) were performed on 10 patients with anterior skull base meningiomas and 10 patients with sphenoid ridge meningiomas. All these data were transferred to Dextroscope virtual reality system, and reconstructed. Then meningiomas, skull base, brain tissue, drainage vein and cerebral arteries were displayed within the system, and their anatomic relationships were evaluated. Also, the simulation operations were performed.

RESULTS

For parasagittal and falcine meningiomas, the relationships of tumor with drainage vein and superior sagittal sinus were clearly displayed in the Dextroscope system. For anterior skull base and sphenoid ridge meningiomas, the relationships of tumor with bilateral internal carotid arteries, anterior cerebral arteries, middle cerebral arteries and skull base were vividly displayed within the virtual reality system. Surgical planning and simulation operation of all cases were performed as well. The real operations of all patients were conducted according to the simulation with well outcomes.

CONCLUSIONS

According to the virtual reality planning, neurosurgeons could get more anatomic information about meningioma and its surrounding structures, especially important vessels, and choose the best approach for tumor resection, which would lead to better prognosis for patients.

[Resection of brainstem cavernous malformations via lateral approaches]

OBJECTIVE

To explore the surgical indications and efficacy of lateral approaches in the removal of brainstem cavernous malformations retrospectively.

METHODS

From July 1999 to June 2008, 10 cases of brainstem cavernous malformations were removed via lateral approaches. Four of them had reached the lateral pial surface and 6 were covered by parenchyma or glial tissue. Three lesions were located dorsal to the cranial nerve roots and 4 lesions rostral to the facial nerve root. All 7 lesions were removed via the retrosigmoidal approach. Far lateral approach was used for 2 cases with the lesions ventral or caudal to the posterior cranial nerves. Subtemporal approach was adopted in 1 patient with the lesion ventral and rostral to the trigeminal nerve. The preoperative visual reality technique, in combination with intraoperative neuronavigation, was employed in the recent 3 cases to select a safe entry point on the surface of brainstem and a surgical corridor so as to maintain minimal damage to the surrounding fiber tracts and cranial nerve nuclei.

RESULTS

Total lesion removal was achieved in all patients. Four cases of associated venous malformation were all preserved. The mean NIHSS score was 1.1 after a mean post-operative follow-up of 41 months. Eight patients improved, 1 worsened and 1 remained unchanged versus the preoperative state.

CONCLUSION

Lateral approaches are recommended for lesions reaching the lateral glial surface or accessible via the lateral safe entry zone approaches.