Emissary veins and pericerebral cerebrospinal fluid in trigonocephaly: do they define a specific subtype?

INTRODUCTION: The premature fusion of the metopic suture may be associated with the presence of emissary veins (EV) and abnormally large pericerebral cerebrospinal fluid (CSF) spaces which suggest an associated focal disturbance in CSF dynamics. The incidence of such findings and their potential significance in terms of management of the disease have not been fully elucidated. The aim of this study is to investigate whether these phenomena identify specific subtypes of trigonocephaly. In such a direction, we evaluated the volume of the pericerebral CSF spaces and their relationship to the morphology ("Ω," "V," or flat type) of the prematurely fused metopic suture and to the value of the interfrontal angle value on the grounds of computed tomographic (CT) scan examinations. METHOD: The preoperative brain CT scans of 74 children (52 boys, 22 girls) with trigonocephaly who had undergone fronto-orbital remodeling were evaluated. The volume of the pericerebral CSF spaces and the value of the interfrontal angle were calculated. The type of intracranial notch was studied and classified according to its shape on the preoperative CT scan: a groove "Ω," a ridge/"V" ridge or absent when flat and evidence of emissary veins related to the abnormally fused suture. RESULTS: Preoperatively, an endocranial metopic groove or ridge was seen in 70% of the children. Emissary veins were identified in 34 of 74 patients (45%), at a mean distance of 2.04 cm (1.18-2.94 cm) from the nasion. The presence of large pericerebral CSF spaces significantly correlated with the presence of EV (p < 0.05), with the "Ω" type (p < 0.05) and with interfrontal angles under 134° (p < 0.005). CONCLUSIONS: Metopic suture early fusion shows an association between EV, pericerebral CSF spaces, and the "Ω" groove appearance of the suture. This association identifies a specific subgroup in which the presence of emissary veins and large pericerebral CSF spaces is an indicator of local venous hypertension due to the sagittal sinus constriction within an osseous groove created by the abnormal suture fusion process. The implications for the surgical management and long-term results as compared to trigonocephalic children with small or absent normal peripheral spaces and EV are still to be determined.

Pre-radiation chemotherapy improves survival in pediatric diffuse intrinsic pontine gliomas.

BACKGROUND: The median survival of patients with diffuse intrinsic pontine glioma (DIPG) remains less than 1 year. The BSG 98 pre-irradiation chemotherapy protocol showed a significant increase in overall survival. In contrast to current treatment strategies, patients did not have to undergo surgical stereotactic biopsy, which can sometimes lead to complications, to be included in this protocol. MATERIALS AND METHODS: We retrospectively reviewed all the cases of DIPG that were treated in our department from September 15, 2004 to September 15, 2014. We compared the group of patients who followed our BSG 98 protocol to those who were treated with new targeted therapy protocols where systematic biopsy was required. RESULTS: Patients in the BSG 98 protocol were treated with BCNU, cisplatin, and methotrexate, followed by radiation at disease progression. Targeted therapy protocols included radiation therapy along with treatment by erlotinib, cilengitide, or an association of nimotuzumab and vinblastine. Sixteen patients were treated with the BSG 98 protocol, and 9 patients were treated with new targeted therapy protocols. Median overall survival was significantly higher in the BSG 98 group compared to the targeted therapy group (16.1 months (95 % CI, 10.4-19.0) vs 8.8 months (95 % CI 1.4-12.3); p = 0.0003). An increase in the median progression-free survival was observed (respectively, 8.6 vs 3.0 months; p = 0.113). CONCLUSION: The present study confirms that the BSG 98 protocol is one of the most effective current treatment strategies for DIPG. It may be used as the control arm in randomized trials investigating the use of innovative treatments and may be proposed to families who are averse to biopsy.

Posterior fossa ependymoma in children: A long-term single-center experience.

INTRODUCTION: Ependymomas in the posterior fossa have poor prognosis. This study reports a single-center pediatric series, focusing on the value of surgical resection. MATERIAL AND METHODS: A single-center retrospective study included all patients operated on by the senior author (CM) for posterior fossa ependymoma from 2002 to 2018. Medical and surgical data were extracted from the hospital's medical database. RESULTS: Thirty-four patients were included. Age ranged from 6 months to 18 years, with a median of 4.7 years. Fourteen patients underwent initial endoscopic third ventriculocisternostomy before the direct surgical resection. Surgical removal was complete in 27 patients. There were 32 surgeries for second-look, local recurrence or metastasis despite complementary chemotherapy and/or radiotherapy. Twenty patients were WHO grade 2 and 14 grade 3. Sixteen patients showed recurrence (47%). Overall survival was 61.8% at a mean 10.1 years' follow-up. Morbidities comprised facial nerve palsy, swallowing disorder, and transient cerebellar syndrome. Fifteen patients had normal schooling, 6 had special assistance; 4 patients reached university, 3 of whom experienced difficulties. Three patients had a job. CONCLUSION: Posterior fossa ependymomas are aggressive tumors. Complete surgical removal is the most important prognostic factor, despite risk of sequelae. Complementary treatment is mandatory, but no targeted therapy has so far proved effective. It is important to continue the search for molecular markers in order to improve outcomes.

Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study.

AIMS: Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification. METHODS: A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival. RESULTS: The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres. CONCLUSIONS: The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

A new approach of crenellated fronto-orbital advancement for the management of trigonocephaly: Technical note.

Trigonocephaly is a craniosynostosis characterized by a premature fusion of the metopic suture associating a characteristic triangular head shape, with a frontal medial crest and hypotelorism. Various techniques have been described for its surgical treatment which is usually performed during the first year of life. However, there might be cases with a late referral, after the age of one year. One of the technical issues with a fronto-orbital advancement surgery in a child over one year of age is that there is a significant risk of persistent residual bone defects. This article describes a surgical technique of crenellated fronto-orbital advancement for correcting trigonocephaly in children over one year of age, allowing to reduce residual bone defects.

Surgical management of posterior fossa medulloblastoma in children: The Lyon experience.

INTRODUCTION: Modern approach for the treatment of posterior fossa medulloblastomas remains a challenge for pediatric neurosurgeons and pediatric oncologists and requires a multidisciplinary approach to optimize survival and clinical results. MATERIAL AND METHODS: We report the surgical principles of the treatment of posterior fossa medulloblastomas in children and how to avoid technical mistakes especially in very young patients. We also report our experience in a series of 64 patients operated from a medulloblastoma between 2000 and 2018 in Lyon. RESULTS: All patients had a craniospinal MRI. Eighty-one percent of the patients (n=50) had strictly midline tumor while 19% (n=14) had lateralized one. Eleven percent (n=7) had metastasis at diagnosis on the initial MRI. Forty-one percent (n=29) had an emergency ETV to treat hydrocephaly and the intracranial hypertension. All patient underwent a direct approach and a complete removal was achieved in 78% (n=58) of the cases on the postoperative MRI realized within 48h postsurgery. Histological findings revealed classical medulloblastoma in 73% (n=46), desmoplastic medulloblastoma in 17% (n=11) and anaplastic/large cell medulloblastoma in 10% (n=7). Patients were classified as low risk in 7 cases, standard risk in 30 cases and high risk in 27 cases. Ninety-six percent (n=61) of the patient received radiotherapy. Seventy-six percent (n=48) received pre-irradiation or adjuvant chemotherapy. At last follow-up in December 2018, 65% (n=41) of the patient were in complete remission, 12% (n=8) were in relapse and 27% (n=15) had died from their disease. The overall survival at five , ten and fifteen years for all the series was of 76%, 73% and 65.7% respectively. CONCLUSIONS: Medulloblastomas remain a chimiosensible and radiosensible disease and the complete surgical removal represents a favorable prognostic factor. The extension of surgery has also to be weighted in consideration of the new biomolecular and genetic knowledge that have to be integrated by surgeons to improve quality of life of patients.

Cranioplasty for bone defects after craniosynostosis surgery. Case series with literature review.

INTRODUCTION: Surgical treatment of craniosynostosis in children may generate secondary cranial vault defects by incomplete ossification process. The incidence of cranial defects after craniosynostosis surgery is poorly reported in the literature with a variable incidence of 0.5% to 18.2%. To better understand the impact and management of the cranial defects after craniosynostosis surgery, we selected and reviewed al cranioplasties that met this criterion between 2002 and 2019. PATIENTS AND METHOD: We found 41 patients (28 M and 13 F) operated between January 2002 to January 2019 who underwent cranioplasty for cranial defects secondary to craniosynostosis surgery in the infancy. All patient were at least 5 years old (range 5 to 17 years, median 11). The indication was aesthetic in 28 patients and for headaches, learning difficulties or changes in the cerebral blood flow in 13 patients. The material used in cranioplasty was the poly-methyl-methacrylate (PMMA) in 40 patients and customized porous hydroxyapatite (CPHA) in 1 patient. RESULTS: The mean follow-up period after cranioplasty was of 37 months (range 2 to 125 months, median of 27 months). In the postoperative period there were no mortality nor neurological complications. There were 3 cases (7%) of superficial local postoperative wound infection but with no evidence of long-term infection. The long-term CT scan follow-up showed no material migration, dislocation or fractures. CONCLUSION: Considering the characteristics of the cranial vault after craniosynostosis surgery the treatment by cranioplasty with heterologous materials appears to be feasible thus avoiding donor site morbidity. For selected cases with small defects, our experience shows that the use of PMMA may be a safe alternative for the cranial vault repair in children older than 5 years.

Positional cranial deformation in children: A plea for the efficacy of the cranial helmet in children.

BACKGROUND: Cranial deformations have historically aroused the interest of people worldwide. One of the more debated points about positional plagiocephaly is the choice of the treatment. In this article, the senior author (CM) shares his experience on almost 30 years of use of the helmet molding therapy in children with deformation plagiocephaly. METHODS AND POPULATION: We retrospectively and systematically reviewed the cases of 2188 patients (75% males and 25% females) presenting positional head deformity and treated between 1991 and 2013 with a cranial helmet. To assess the effectiveness of the helmet, we compared the cranial index in bilateral plagiocephaly and the Cranial Diagonals Difference (CDD) in unilateral plagiocephaly at the beginning and at the end of the treatment. RESULTS: The cranial indexes ranged between 94.4% and 124.2% before the treatment and decreased significantly between 86.8% and 121.4% after the treatment (P<0.01). The CDD ranged between 0.3 cm and 4.5 cm with an average of 1.50±0.54 cm before the treatment and decreased significantly between 0.1 cm and 2.5 cm with an average of 0.72±0.37 cm after the treatment (P<0.01). For unilateral plagiocephaly, at the beginning of the treatment, 2.5% children presented a mild plagiocephaly, 19.6% a moderate plagiocephaly and 77.9% a severe plagiocephaly. At the end of the treatment, the deformation was classified as mild in 40.2% children, moderate in 44.3% children and severe in 15.5% children with significantly less children in the most severe subgroups (P<0.01) Facial symmetry pre-existed before the treatment in 13.7% of children. This rate was significantly increased at the end of the treatment to 66.7% (P<0.01). In only 8 cases (0.2%), the helmet therapy did not allow to obtain correct clinical results and a surgical posterior cranial remodeling was performed. CONCLUSIONS: The results observed in this series confirms that cranial helmet is a simple and well tolerated alternative which bring satisfying results. Its success implies a good collaboration with parents and a management both by orthoptist, physiotherapist and doctor. Nevertheless, it remains many controversies in the literature concerning in particular long-term cosmetic and functional outcomes. A long-term multicentric prospective study could enable to remove doubts.

Sagittal suture craniosynostosis or craniosynostoses? The heterogeneity of the most common premature fusion of the cranial sutures.

BACKGROUND: Scaphocephaly is usually defined as the deformation of the skull resulting from the premature fusion of the sagittal suture. It is the most common type of craniosynostosis, and can be easily recognized on simple clinical examination. Its pathophysiology is easy to understand and to confirm on neuroradiological examination. In contrast, surgical indications are still somewhat controversial, the dispute mainly concerning therapeutic versus esthetic objectives. In recent years, however, several studies have challenged these basic and relatively simplistic interpretations of the pathophysiology of the condition. MATERIALS AND METHODS: To assess the heterogeneity of scaphocephaly, we reviewed cases of scaphocephaly operated on at the Hôpital Femme-Mère-Enfant, Lyon University Hospital, France during a 10-year period (2008-2017) and performed a review of the literature on scaphocephaly and sagittal suture closure. RESULTS: During the 10-year period, 401 children were operated on for a scaphocephaly at the Hôpital Femme Mère Enfant, Lyon University Hospital. Mean age at surgery was 1.14 years, for a median 0.7 years (range, 4 months to 8. 5 years). Several subtypes could be distinguished according to morphology, intracranial findings on imaging, patient age, and etiology associated to the sagittal synostosis. Two main surgical techniques were used to correct the malformation, depending on patient age, type of deformation and the surgeon's preference: cranial vault remodeling with occipital pole widening, with the patient in a prone position, and parietal enlargement with or without forehead remodeling, in dorsal decubitus. CONCLUSIONS: The complexity and heterogeneous nature of sagittal synostoses depend on different pathogenic mechanisms leading to and interfering with the skull abnormalities: abnormalities of CSF dynamics, possibly associated with systemic alterations, accounting for the varied postoperative morphological and functional course, in terms of cognitive impairment and late complications (notably intra-cranial pressure elevation). However, the real impact of such heterogeneous clinical presentations on surgical indications and surgical results remains to be elucidated.

[Psychological support for children operated on for craniosynostosis and their family. Some thoughts for the craniofacial surgeon]. / Suivi psychologique des enfants opérés de craniosténoses et de leurs proches. Quelques éléments de réflexions pour le chirurgien craniofacial.

What is the impact on child and family when they receive a diagnosis of craniostenosis? And what is the impact of surgery? What is the role of the clinical psychologist in accompanying the child and family, especially during hospital stay and surgery time? We present a few thoughts that help understand the psychological processes at work in case of craniostenosis, giving a little hint of the impact on the life of the child and family - which surgeons, preoccupied by more technical questions, sometimes tend to overlook.

[Neuropsychological consequences of craniosynostosis: Non-syndromic scaphocephaly]. / Le retentissement neuropsychologique de la craniosténose : cas de la scaphocéphalie non syndromique.

BACKGROUND: Scaphocephaly increases the rate of some modifications of cognitive and mood profile in a manner that remains to be elucidated. OBJECTIVE: We aimed to describe the impact of scaphocephaly on neuropsychological profile and more particularly on the executive functions. PATIENTS AND METHODS: An experimental group of 19 children older than 5 years, operated on for scaphocephaly, was compared with a control group of 10 children operated on for trigonocephaly, using IQ tasks, attention tasks and mood scales. A group of 6 children from 2 to 4 years old, operated on for scaphocephaly, and a group of 6 children with non-operated scaphocephaly are also described. RESULTS: Both the experimental group and the control group showed unchanged IQ, whereas attention deficit and anxiety disorder were more frequent in the experimental group. Cognitive profiles differed between groups, with a higher rate of impaired inhibitory control of visual processing in the scaphocephaly group, contrasting with a higher rate of impaired auditory verbal working memory in the trigonocephaly group. Comparable profiles were also found in groups of younger or non-operated children with scaphocephaly. CONCLUSIONS: Many children with scaphocephaly must cope with a specific neuropsychological profile throughout development. This study suggests the interest for these children and their families of specific follow-up in reference centers.

Histological features and expression of enzymes implicated in melatonin synthesis in pineal parenchymal tumours and in cultured tumoural pineal cells.

Pineal parenchymal tumours (PPT) are rare neoplasms and there have been few in vitro studies. Their capacity for synthesizing and secreting melatonin has been only partially examined. We investigated the presence of messenger RNA (mRNA) encoding tryptophan hydroxylase (TPH), arylalkylamine N-acetyltransferase (AANAT), hydroxyindol-O-methyltransferase (HIOMT), three enzymes involved in melatonin synthesis, and c-myc, a tumoural marker, in 10 PPT, one papillary tumour of the pineal region (PTPR), cell cultures derived from four PPTs and from three other tumours of the pineal region, and in normal pineal gland. Moreover, protein expression of TPH was investigated in three PPT and PTPR. Quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry were used and the melatonin production by tumoural cells in vitro was analysed by radioimmunoassay. We showed that all the tumoural tissues and cells contained c-myc mRNA. mRNAs encoding TPH, AANAT and HIOMT were detected in all PPT, suggesting that tumour cells can synthesize melatonin. Only PPT expressed TPH protein. Cultured cells lost expression of transcripts throughout passages even if ultrastructural study revealed the presence of characteristic organelles in these tumoural cells. Nevertheless, the basal secretion of melatonin observed in one PPT culture is in favour of a maintained melatonin production and secretion by tumoural pinealocytes, but melatonin production was not stimulated by a beta noradrenergic agonist. Moreover, PTPR never expressed mRNA encoding TPH, AANAT and HIOMT. Our results may contribute to a better understanding of the biology of PTT and PTPR and may help to the diagnosis of these rare tumours.

[Why a hydroxyapatite cranioplasty can be used to repair a cranial bone defect in children: Experience of 19 cases]. / Pourquoi peut-on utiliser une plastie en hydroxyapatite pour réparer une perte de substance osseuse de la boîte crânienne chez les enfants : expérience à propos de 19 cas.

INTRODUCTION: The use of an autologous bone graft to repair a cranial bone defect is sometimes impossible in pediatric cases. CUSTOMBONE® made with hydroxyapatite is a good alternative in these indications for neurosurgeons. MATERIAL AND METHODS: We present a pediatric series of 19 children who benefited from a cranioplasty using CUSTOMBONE®. Their ages ranged between 8 months and 13 years with a mean of 6 years and 2 months. The most frequent indication was a cranioplasty after a post-traumatic decompressive craniectomy. RESULTS: No complications were reported. Cosmetic outcome was satisfactory in all patients. Only one plasty needed to be changed after a severe head trauma during the postoperative period. The assessment of cerebral blood flow was improved in all patients postoperatively. Complete ossification of the plasty is a long process. The mean time for the ossification to begin was 13 months (range: 3-22 months). The mean follow-up was 2.7 years. DISCUSSION: The excellent integration of the prosthesis is related to the accuracy of the reconstruction of the preoperative model. The minimum thickness of the plasty (4mm) could represent a challenge in very young children. One limitation is the cost, which remains high. CONCLUSION: CUSTOMBONE® met the criteria of protection and restoration of the normal intracranial physiology with good cosmetic results, which are necessary qualities for excellent clinical outcome.

History of the pineal region tumor.

The pineal gland has interested humans from millenniums. In this paper we review back in the history and the evolution of the pineal gland surgery. Originally, this surgery used to carry a high rate of morbidity and mortality. Nowadays the development of the anesthetic, radiological, surgical and intensive care techniques have been responsible of an improvement of the surgical results and better quality of life. It is always interesting to know from where we come.

Pineal tumours: Experience of the French National Register and the Lyon School, results and considerations.

The experience of the French National Register of pineal tumours and the experience of the Lyon School are reported. Data were collected from 26 French neurosurgical centres from 1989 in Lyons and in other centres from 1997. For radiological and pathological studies, 517 cases were considered while only 452 with sufficient clinical and follow-up data were retained for further analysis. These data highlight the importance of the initial diagnosis for a therapeutic strategy that can be completely different in cases of pineal or germ cell tumours. As regards the latter, chemotherapy and radiotherapy can avoid surgery. Pineocytomas are benign lesions and their complete removal guarantees the cure. Pineal parenchymal tumours with intermediate differentiation (PTT-ID) require complete removal and complementary treatment in cases of histological abnormalities with approximately 66% of patients who remain alive. Pineoblastomas have a poor prognosis and the rate of survival in the French National Register is only 33% of cases. Germinomas can be treated with chemotherapy or radiotherapy alone and generally the indication for surgical removal is limited to residual tumours. The rate of survival is 64% at 10 years. For papillary tumours of the pineal region (PTPR) complete removal is a good prognostic factor. Radiotherapy seems to be effective in cases of residual tumours. The experience and results with radiosurgery treatment have been limited in the French national and Lyon experience.

Incidence of pineal tumours. A review of the literature.

The knowledge of the incidence of pineal tumours is important not only for diagnostic care but also for its therapeutic programme. We reviewed the incidence of pineal tumours reported in literature in an attempt to establish if a difference existed between pineal gland tumours and the pineal region tumours as different authors use both expressions to indicate the same thing. The rate of frequency of these tumours is useful to guide the therapeutic choice for patients as the decisional tree is completely different for either germ cell tumours, pineal gland tumours or pineal gliomas and eventually papillary tumours of the pineal region. According to the French Register of pineal tumours, true pineal tumours represent: 27% pineal parenchymal tumours (PPT), 27% germ cell tumours, 17% gliomas, 8% papillary tumours. True pineal gland tumours are represented by: pineocytomas - (13%), pineal parenchymal tumours with intermediary differentiation PTT-ID - (66%) and pinealoblastomas - (21%). There was no statistical difference found between the French register and the Lyon series concerning histological diagnosis. It seemed to us important to discover its true incidence by comparing the data published in the literature and to stress the utility of the French Register for these uncommon tumours not only for recording new histological cases but also to document clinical symptomatology, therapeutic programmes, length of follow-up and clinical results for each patient treated. A better understanding of their natural history and improved evaluation of different treatments and their complications should contribute to improve clinical results.

Cranial vault expansion with the split bone flap technique in shunt-related craniosynostosis.

INTRODUCTION: Shunt-related craniosynostosis causing craniocerebral disproportion represents a particular complication of the treatment of hydrocephalus. When the modification of the shunt opening pressure does not improve the symptomatology, surgery for correction of craniocerebral disproportion is indicated. We present the results and advantages of the split bi-frontal bone technique that is a modification of the previous used frontal bone advancement technique. PATIENTS AND METHODS: We retrospectively reviewed 5 patients with iatrogenic craniosynostosis treated in our institution from 1995 to 2012. A splitting bi-frontal bone flap that is left floating posteriorly was performed to increase the cranial volume. RESULTS: All patients were cured. This technique increases the volume of the skull favoring the expansion of the brain and allows good cosmetical results. No perioperative complications were reported. DISCUSSION: The fact that the brain has a more appropriate volume allows the disappearance of the clinical symptomatology related to the split ventricle syndrome. The advantage is the respect of the fronto-orbital shape in children and adults with the same results of the classic frontal advancement in terms of volume expansion. The study of cerebral blood flow confirms the increase of the cerebral blood perfusion and the improvement of the regional cerebral blood flow in borderline regions. We preconize, for the treatment of slit ventricle syndrome, the bi-frontal split technique in children and adults for its efficacy, the low rate of complications and the respect of aesthetical constraints.

The management of pineal tumors as a model for a multidisciplinary approach in neuro-oncology.

The management of pineal tumors is a model for multidisciplinarity. Apart from an emergency situation that requires immediate shunting of cerebrospinal fluid (CSF), the initial discussion should involve at least a radiologist, a surgeon, a neurologist and an oncologist. The initial decision is whether obtaining a histological proof is obligatory. It depends on age and ethnicity, site (mono- or bifocality), presence of markers in serum as well as CSF, and/or of malignant cells in the CSF. In cases of marker elevation indicating a germ cell tumor, front line chemotherapy can avoid dangerous immediate surgery. When histological proof is required, the extent of surgery should be discussed, aiming either only at obtaining tissue or removal. If a germ cell tumor is detected, treatment will include a cisplatin-containing chemotherapy followed by focal or ventricular irradiation. Tumors of the pineal parenchyma will be treated according to grade, either by surgery alone (pinealocytoma) or chemo-radiotherapy (pinealoblastomas). Similarly, gliomas will be treated depending on their grade with several different possible lines in low grade, and usually radio-chemotherapy in high grade. A careful balance between improved survival rates and decreased long-term side effects will guide the decisions of all these specialists.

Anatomical, molecular and pathological consideration of the circumventricular organs.

BACKGROUND AND PURPOSE: Circumventricular organs (CVOs) are a diverse group of specialised structures characterized by peculiar vascular and position around the third and fourth ventricles of the brain. In humans, these organs are present during the fetal period and some become vestigial after birth. Some, such as the pineal gland (PG), subcommissural organ (SCO) and organum vasculosum of the lamina terminalis (OVLT), which are located around the third ventricle, might be the site of origin of periventricular tumours. In contrast to humans, CVOs are present in the adult rat and can be dissected by laser capture microdissection (LCM). METHODS: In this study, we used LCM and microarrays to analyse the transcriptomes of three CVOs, the SCO, the subfornical organ (SFO) and the PG and the third ventricle ependyma of the adult rat, in order to better characterise these organs at the molecular level. Furthermore, an immunohistochemical study of Claudin-3 (CLDN3), a membrane protein involved in forming cellular tight junctions, was performed at the level of the SCO. RESULTS: This study highlighted some potentially new or already described specific markers of these structures as Erbb2 and Col11a1 in ependyma, Epcam and CLDN3 in the SCO, Ren1 and Slc22a3 in the SFO and Tph, Anat and Asmt in the PG. Moreover, we found that CLDN3 expression was restricted to the apical pole of ependymocytes in the SCO.

Sensorimotor mapping of the human cerebellum during pineal region surgery.

BACKGROUND: The cerebellum is a fundamental structure of the central nervous system. However, in humans, its anatomo-functional organization and the processes through which this organization adapts in response to injuries remain widely unknown. METHODS: Motor and somatosensory evoked potentials were used to map functional representations in the posterior cerebellum of patients with extra- and intracellebellar injuries. Extracerebellar patients had injuries outside the cerebellum (e.g. pineal region, quadrigeminal plate) while intracerebellar patients had injuries within the cerebellum. Data were collected in 20 extracerebellar patients for motor representations. Only preliminary data were gathered for somatosensory representations and intracerebellar patients. RESULTS: In extracerebellar patients, electrical stimulation induced muscle contractions in the ipsilateral hemibody. These representations were somatotopically organized with large overlaps between the face and upper limb in the superior posterior cerebellum and the upper and lower limb in the inferior posterior cerebellum. Neck muscles were represented in the oculomotor vermis. In intracerebellar patients, preliminary data seem to indicate that motor plasticity is achieved by recruiting the contralesional (healthy) cerebellar hemisphere. CONCLUSIONS: Although still ongoing, this project could eventually lead to an improvement of the surgical treatment of patients with lesions of the posterior fossa, by improving our knowledge of cerebellar organization and the process of post-lesional plasticity.