Posterior Fossa Tumors Research Articles

Influencing factors, surgical management, and predictors of posterior fossa tumors with hydrocephalus in children

Background: Hydrocephalus is a common disease in neurosurgery. In pediatric central nervous system tumors, the proportion of posterior fossa tumors (PFTs) in children is high, hydrocephalus is often the first manifestation, and some cases have de novo or aggravated hydrocephalus after surgery. Objective: To conclude some controversies about the treatment methods and timeline of PFT with hydrocephalus. Methods: This article reviews the latest progress in the literature and practical problems encountered in clinical practices. Results: For most children, surgical drainage is the most effective treatment; however, medical treatment can be performed before surgery or a definite diagnosis is made. In children with PFT, the risk of hydrocephalus can be initially predicted according to the condition of the child, which has clear clinical significance for the selection of treatment methods and the evaluation of related prognosis. Conclusion: PFT is a common site for CNS tumors in children, and its clinical manifestations are often hydrocephalus-related. According to the condition of pediatric patients, early prediction of the risk of hydrocephalus has clear clinical significance for the selection of treatment methods and the evaluation of related prognoses.

Consensus guidelines for the management of posterior fossa tumour for low- and middle-income countries.

The posterior fossa is a limited compartment therefore lesions compressing its structures can result in devastating outcomes. It can cause significant neurological deficit due to mass effect on critical structures and hydrocephalus. Due to the nature of the infratentorial region, urgent surgical intervention is often the first-line option. Surgical neuro-oncologists guide patients and caregivers through the course of this disease and to inform them about the various options for management and long-term outcome optimisation. There is currently conflicting data; however, institutional experiences can guide us towards achieving improvements in surgical outcomes and quality of life. Advances in molecular classifications coupled with highdose radiation treatment improve our capacity for improving overall survival in these patients. Common childhood tumours are ependymomas, medulloblastomas, and juvenile pilocytic astrocytomas, while adults often present with metastases, and less commonly, cerebellar haemangioblastomas and gliomas. This paper outlines management strategies with consideration for multidisciplinary care and resourcelimited settings.

Delayed symptomatic cerebral vasospasm following vestibular schwannoma resection: illustrative case.

Symptomatic cerebral vasospasm following posterior fossa extraaxial tumor resection is a rare phenomenon, with only 13 cases previously reported in the literature. The condition appears similar to vasospasm following supratentorial tumor resection, intraaxial posterior fossa tumor resection, and aneurysmal subarachnoid hemorrhage (aSAH). The majority of patients were not evaluated for vasospasm prior to symptom onset, leading to a delay in diagnosis. The authors present their experience in a 56-year-old female who developed delayed cerebral vasospasm after excision of a solid-cystic vestibular schwannoma. Routine postoperative brain computed tomography showed evidence of subarachnoid hemorrhage in the basal cisterns. She was discharged on the 9th postoperative day. On the 11th day after tumor excision, she developed left hemiparesis, dysarthria, and dysphagia and was readmitted. Angiography confirmed bilateral diffuse cerebral vasospasm. The patient responded to standard hyperdynamic therapy used for vasospasm secondary to aSAH. Symptomatic distant cerebral vasospasm after posterior fossa extraaxial tumor excision is a rare but challenging complication with a very high morbidity rate in reported cases. A high index of suspicion is required for early diagnosis and prompt management for a favorable outcome.

REhabilitation Approaches in CHildren with cerebellar mutism syndrome (REACH): An international cross-disciplinary survey study.

Pediatric cerebellar mutism syndrome (pCMS) can occur following resection of a posterior fossa tumor and, although some symptoms are transient, many result in long-lasting neurological deficits. A multi-disciplinary rehabilitation approach is often used in cases of pCMS; however, there have been no clinical trials to determine gold standards in rehabilitation practice in this population, which remains a research priority. The purpose of this study was to identify and compare intervention practices used in pCMS throughout the disciplines of occupational and physical therapy, speech-language pathology, and neuropsychology across geographic regions. A 55-question e-survey was created by an international multidisciplinary research group made up of members of the Posterior Fossa Society and sent to rehabilitation professionals in pediatric neuro-oncology centers in the US, Canada, and Europe. Although some differences in the type of intervention used in pCMS were identified within each discipline, many of the targeted interventions including dose, frequency, and intensity were similar within disciplines across geographic regions. In addition, there were common themes identified across disciplines regarding challenges in the rehabilitation of this population. These results provide a foundation of current practices on which to build future intervention-based clinical trials.

Terson’s Syndrome due to Ependymoma: A Rare Case Report

Abstract
 Introduction : Terson's syndrome is often associated with subarachnoid hemorrhage. Other reported causes, include trauma, tumors, hypertension, perioperative and postoperative intracranial hemorrhage, or increased intracranial pressure. This case demonstrates a unique pathogenesis of Terson's syndrome.
 Case Illustration : A 14-year-old boy presented with the blurred vision on both eyes 3 weeks ago, accompanied with nausea, vomiting, and headache, with normal blood pressure measurement (126/80mmHg). He also had a history of head injury. His visual acuity was 6/20 uncorrected with pinhole on both eyes. Both intraocular pressures within normal limits. The anterior segment showed bilateral mid-dilated reactive pupil. Funduscopy revealed bilateral papilledema with peripapillary hemorrhage, similar to retinal vein occlusion, which is suggestive with Terson’s Syndrome. Magnetic Resonance Imaging (MRI) scan showed an ependymoma mass. We consulted this case with Pediatric Neurosurgeon, who planned for ventriculoperitoneal shunt with craniotomy tumor removal.
 Discussion : Terson's syndrome now defined as any intraocular hemorrhage associated with intracranial hemorrhage or elevated intracranial pressures. In this case, the etiology was thought to be increased intracranial pressure, which may be caused by ependymoma. Ependymoma is one of the most common central nervous system tumors in children. Intraocular hemorrhage in Terson’s syndrome is often self-limiting, but ependymoma needs neurosurgical intervention, which has lower survival rates for children with posterior fossa tumors.
 Conclusion : There are still controversies regarding the pathogenesis of Terson's syndrome. Not the occlusion, but the compression of the central retinal vein, by the increased pressure of cerebrospinal fluid due to high intracranial pressure, which increases the retinal venous pressure and causes retinal hemorrhage.

Characterizing the association between CSF biomarkers and risk for ventriculoperitoneal shunt following posterior fossa tumor resection in a case-control study

BackgroundRecalcitrant hydrocephalus necessitating permanent cerebrospinal fluid (CSF) diversion is a known complication after resection of a posterior fossa tumor (PFT). Various CSF contents, such as protein and other markers, have been variably correlated with the need for permanent CSF diversion. This study aims to evaluate which CSF laboratory values are associated with permanent CSF diversion following PFT resection in adults. MethodsThis study queried our multi-institutional database (Central Nervous System Tumor Outcome Registry at Emory; CTORE) consisting of 617 adult patients with PFT resections from 2006 to 2021. Retrospective data was collected from the 89 patients of this cohort that required EVD placement. Patients were stratified into two groups: those that required a shunt following EVD removal (n = 30) and those that did not (n = 40). CSF variables collected included glucose, protein, nucleated cell count, and presence of infection. An unadjusted logistic regression was performed to assess exposures associated with shunt requirement and unadjusted odds ratios (ORs) and their associated 95 % confidence intervals (CIs) were obtained. ResultsImmediately following surgery, no CSF variables were significantly associated with shunt placement. Except for post-operative CSF being not-clear (OR: 4.15 (1.47–12.56), p = 0.009) and CSF glucose (OR: 0.97 (1.03–1.07), p = 0.031) all other variables were not significantly associated with shunt at time point 2. ConclusionIn our retrospective analysis, most routinely collected CSF values were not associated with permanent CSF diversion via a ventriculoperitoneal shunt following PFT resection. Further research is needed to identify other potential predictive markers.

Anaplastic Lymphoma Kinase (ALK) in Posterior Cranial Fossa Tumors: A Scoping Review of Diagnostic, Prognostic, and Therapeutic Perspectives

Anaplastic Lymphoma Kinase (ALK) has been implicated in several human cancers. This review aims at mapping the available literature on the involvement of ALK in non-glial tumors localized in the posterior cranial fossa and at identifying diagnostic, prognostic, and therapeutic considerations. Following the PRISMA-ScR guidelines, studies were included if they investigated ALK’s role in primary CNS, non-glial tumors located in the posterior cranial fossa. A total of 210 manuscripts were selected for full-text review and 16 finally met the inclusion criteria. The review included 55 cases of primary, intracranial neoplasms with ALK genetic alterations and/or protein expression, located in the posterior fossa, comprising of medulloblastoma, anaplastic large-cell lymphoma, histiocytosis, inflammatory myofibroblastic tumors, and intracranial myxoid mesenchymal tumors. ALK pathology was investigated via immunohistochemistry or genetic analysis. Several studies provided evidence for potential diagnostic and prognostic value for ALK assessment as well as therapeutic efficacy in its targeting. The available findings on ALK in posterior fossa tumors are limited. Nevertheless, previous findings suggest that ALK assessment is of diagnostic and prognostic value in medulloblastoma (WNT-activated). Interestingly, a substantial proportion of ALK-positive/altered CNS histiocytoses thus far identified have been localized in the posterior fossa. The therapeutic potential of ALK inhibition in histiocytosis warrants further investigation.

Extra-axial desmoplastic/nodular medulloblastoma in adult mimicking cerebellar metastasis: reappraisal of this rare presentation with literature review

Introduction and importance: Medulloblastomas are the most common malignant intra-axial brain tumour in paediatric patients and represent 35–40% of posterior fossa tumour types in children between 3 and 9 years of age. Medulloblastomas may also be found in adulthood. These tumours are classified into two groups according to its molecular characteristics and histological type. The desmoplastic/nodular subtype is the second common subtype after the classic one. Only three cases of desmoplastic/nodular extra-axial medelloblastoma have been previously reported in the literature originating from to the cerebellopontine angle. Case presentation: The authors report a new case of an extra-axial desmoplastic/nodular cerebellar medulloblastoma originating outside the cerebellopontine angle and mimicking a solitary cerebellar metastasis in a 49-year-old female patient who presented for a raised intracranial pressure and cerebellar syndrome. Clinical discussion: Medulloblastoma is a malignant embryonal intra-axial tumour of the cerebellum or posterior brain stem that occurs mainly in children. Medulloblastomas may also be found in adulthood. Desmoplastic/nodular medulloblastoma is the second most common type of all medulloblastomas. The intra-axial form is always predominant. Only three cases of extra-axial desmoplastic/nodular medulloblastoma have been reported in the literature. The authors will go through the literature to dissect this rare entity. Conclusion: Although considered a common paediatric intra-axial tumour, there are increasing numbers of solitary cases reporting an extra-axial presentation in different locations of the posterior cerebral fossa even in adulthood. These rare and unusual presentations and locations may mislead the correct diagnosis and delay treatment.

The risk factors for silent aspiration: A retrospective case series and literature review.

Evidence shows that 20%-30% of patients who aspirate do so silently. Research to date has not demonstrated clear evidence to indicate which patients are at higher risk of silent aspiration. Our aim was to use univariate logistic regression analysis of retrospective case review to determine potential patterns of silent aspiration. We conducted a retrospective analysis of 455 fiberoptic endoscopic evaluation of swallowing (FEES) reports. The patients were divided into four groups: G1 - neurological diseases (n = 93), G2 - head and neck surgery (n = 200), G3 - gastroenterological diseases (n = 94) and G4 - other patients (n = 68). Data included the occurrence or absence of saliva penetration or aspiration, of silent fluid/solid food penetration or aspiration, type of penetration or aspiration, occurrence of cranial nerve paresis, radiotherapy and tracheostomy. Univariate logistic regression was used to evaluate independent risk factors of silent aspiration in the study population. Three models with different independent variables were considered. There is a statistically significant difference in the frequency of occurrence of silent penetration and aspiration within the groups (p < 0.001), with intraglutative being most frequent. Fluid and food penetration and aspiration correlated with saliva penetration and aspiration in all groups (p < 0.001). Cranial nerve paresis (IX and X), radiotherapy and tracheostomy correlate with saliva penetration and aspiration (p = 0.020 for cranial nerve paresis; p = 0.004 for radiotherapy; p < 0.001 for tracheostomy). One hundred and fifteen patients (45.81%) in the subgroup of patients with intraglutative aspiration had cranial nerve paresis (IX, X or IX-X). Patients who should be prioritised or considered to be at a higher need of instrumental swallowing evaluation are those with IX and X cranial nerve paresis, tracheostomy and those who have had radiotherapy, with saliva swallowing problems, especially after paraganglioma, thyroid and parathyroid glands and middle and posterior fossa tumour surgery. What is already known on the subject Clinical signs of penetration or aspiration include coughing, throat clearing and voice changes, while silent penetration or aspiration patients aspirate without demonstrating any clinical symptoms. The most common consequences of silent aspiration include aspiration pneumonia, recurrent lower respiratory tract infections and respiratory failure. Additionally, malnutrition and dehydration can be indicators of silent aspiration. Patients may unknowingly reduce their oral intake and lose weight. Retrospective studies have shown that 20%-30% of patients aspirate silently (e.g. patients after stroke, acquired brain injury, head and neck cancer treatment, prolonged intubation). Clinical examination of swallowing can miss up to 50% of cases of silent aspiration. What this paper adds to existing knowledge Currently, silent aspiration is often discussed in neurological literature, but its applications to head and neck surgery are limited. In this study, we identify head and neck surgery patients who should be prioritised or considered to be in higher need of instrumental swallowing evaluation due to a higher risk of silent aspiration. What are the potential or actual clinical implications of this work? Post-treatment structural changes can result in lower cranial nerve paresis (IX, X, XII) and face injury, in which vagus and glossopharyngeal nerves are injured. After tracheostomy and radiotherapy, patients with problems swallowing saliva need careful clinical examination, particularly cranial nerve examination.

National multicentered retrospective review of clinical and intraoperative factors associated with the development of cerebellar mutism after pediatric posterior fossa tumor resection.

Cerebellar mutism (CM) is characterized by a significant loss of speech in children following posterior fossa (PF) surgery. The biological origin of CM remains unclear and is the subject of ongoing debate. Significant recovery from CM is less likely than previously described despite rigorous multidisciplinary neuro-rehabilitational efforts. A national multi-centered retrospective review of all children undergoing PF resection in four midsized Canadian academic pediatric institutions was undertaken. Patient, tumor and surgical factors associated with the post-operative development of CM were reviewed. Retrospective identification of PF surgery patients including those developing and those that did not (internal control). The study identified 258 patients across the 4 centers between 2010 and 2020 (mean age 6.73years; 42.2% female). Overall, CM was experienced in 19.5% of patients (N = 50). Amongst children who developed CM histopathology included medulloblastoma (35.7%), pilocytic astrocytoma (32.6%) and ependymoma (17.1%). Intraoperative impression of adherence to the floor of the 4th ventricle was positive in 36.8%. Intraoperative abrupt changes in blood pressure and/or heart rate were identified in 19.4% and 17.8% of cases. The clinical resolution of CM was rated to be complete, significant resolution, slight improvement, no improvement and deterioration in 56.0%, 8.0%, 20.0%, 14.0% and 2.0%, respectively. In the cohort of children who experienced post-operative CM as compared to their no-CM counterpart, proportionally more tumors were felt to be adherent to the floor of the 4th ventricle (56.0% vs 49.5%), intraoperative extent of resection was a GTR (74% vs 68.8%) and changes in heart rate were noted (≥ 20% from baseline) (26.0% vs 15.9%). However, a multiple regression analysis identified only abrupt changes in HR (OR 5.97, CI (1.53, 23.1), p = 0.01) to be significantly associated with the development of post-operative CM. As a devastating surgical complication after posterior fossa tumor surgery with variable clinical course, identifying and understanding the operative cues and revising intraoperative plans that optimizes the child's neurooncological and clinical outcome are essential.

Multimodal imaging with magnetization transfer and diffusion tensor imaging reveals evidence of myelin damage in children and youth treated for a brain tumor.

The microstructural damage underlying compromise of white matter following treatment for pediatric brain tumors is unclear. We use multimodal imaging employing advanced diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI) MRI methods to examine chronic microstructural damage to white matter in children and adolescents treated for pediatric brain tumor. Notably, MTI may be more sensitive to macromolecular content, including myelin, than DTI. Fifty patients treated for brain tumors (18 treated with surgery ± chemotherapy and 32 treated with surgery followed by cranial-spinal radiation; time from diagnosis to scan ~6 years) and 45 matched healthy children completed both MTI and DTI scans. Voxelwise and region-of-interest approaches were employed to compare white matter microstructure metrics (magnetization transfer ratio (MTR); DTI- fractional anisotropy [FA], radial diffusivity [RD], axial diffusivity [AD], mean diffusivity [MD]) between patients and healthy controls. MTR was decreased across multiple white matter tracts in patients when compared to healthy children, P < .001. These differences were observed for both patients treated with radiation and those treated with only surgery, P < .001. We also found that children and adolescents treated for brain tumors exhibit decreased FA and increased RD/AD/MD compared to their healthy counterparts in several white matter regions, Ps < .02. Finally, we observed that MTR and DTI metrics were related to multiple white matter tracts in patients, Ps < .01, but not healthy control children. Our findings provide evidence that the white matter damage observed in patients years after treatment of pediatric posterior fossa tumors, likely reflects myelin disruption.

Morphological and ultrastructural investigation of the posterior atlanto-occipital membrane: Comparing children with Chiari malformation type I and controls.

The fibrous posterior atlanto-occipital membrane (PAOM) at the craniocervical junction is typically removed during decompression surgery for Chiari malformation type I (CM-I); however, its importance and ultrastructural architecture have not been investigated in children. We hypothesized that there are structural differences in the PAOM of patients with CM-I and those without. In this prospective study, blinded pathological analysis was performed on PAOM specimens from children who had surgery for CM-I and children who had surgery for posterior fossa tumors (controls). Clinical and radiographic data were collected. Statistical analysis included comparisons between the CM-I and control cohorts and correlations with imaging measures. A total of 35 children (mean age at surgery 10.7 years; 94.3% white) with viable specimens for evaluation were enrolled: 24 with CM-I and 11 controls. There were no statistical demographic differences between the two cohorts. Four children had a family history of CM-I and five had a syndromic condition. The cohorts had similar measurements of tonsillar descent, syringomyelia, basion to C2, and condylar-to-C2 vertical axis (all p>0.05). The clival-axial angle was lower in patients with CM-I (138.1 vs. 149.3 degrees, p = 0.016). Morphologically, the PAOM demonstrated statistically higher proportions of disorganized architecture in patients with CM-I (75.0% vs. 36.4%, p = 0.012). There were no differences in PAOM fat, elastin, or collagen percentages overall and no differences in imaging or ultrastructural findings between male and female patients. Posterior fossa volume was lower in children with CM-I (163,234 mm3 vs. 218,305 mm3, p<0.001), a difference that persisted after normalizing for patient height (129.9 vs. 160.9, p = 0.028). In patients with CM-I, the PAOM demonstrates disorganized architecture compared with that of control patients. This likely represents an anatomic adaptation in the presence of CM-I rather than a pathologic contribution.

Reassessing the Related Factors of Hydrocephalus in Pediatric Patients with Posterior Fossa Tumours: 5-year Single-Center Data

Reassessing the Related Factors of Hydrocephalus in Pediatric Patients with Posterior Fossa Tumours: 5-year Single-Center Data

Optimal management of hydrocephalus in children with posterior fossa tumors

Optimal management of hydrocephalus in children with posterior fossa tumors

Five-year follow-up after neurosurgery complicated by facial neuropathy

Botulinum toxin A (BTA) injections are effective for facial neuropathy. However, there is insufficient number of studies devoted to long-term management of these patients. To evaluate the effectiveness and safety of BTA therapy in patients with facial neuropathy after neurosurgical interventions. The study included 86 patients with facial neuropathy after surgical treatment of posterior cranial fossa and cerebellopontine angle tumors. All ones were divided into 2 groups: group I (main) - 57 patients with BTA prescribed early after facial nerve injury, group II (control) - 29 people undergoing exercise therapy, as well as special exercises and acupressure of painful muscle cords. The Sunnybrook Facial Grading Scale (SFGS) was used to assess facial symmetry and synkinesis, the Facial Disability Index (FDI scale) - to assess the quality of life. Overall duration of the study was 5 years (control points: 6 months, 1, 2, 3 and 5 years). The SFGS scores after 1, 2, 3 and 5 years were significantly better in the main group (resting symmetry p<0.01, voluntary movement symmetry p<0.01, synkinesis p<0.01, general condition of facial muscles p<0.01). Scores of physical and social functioning were significantly higher in the main group after 1 (p<0.01), 2 (p<0.01), 3 (p<0.01) and 5 years (p<0.01) after surgery. There was no need to change BTA dosage over 5 years. Thus, this form of BTA may be the most effective for synkinesis of facial muscles. Correction of synkinesis caused by facial neuropathy requires long-term follow-up and long-term treatment. BTA is effective and may be recommended for long-term treatment of these patients.

Outcome of Midline Posterior Cranial Fossa Tumor Surgery with Preoperative Ventriculo - Peritoneal (V-P) Shunt in Children

Outcome of Midline Posterior Cranial Fossa Tumor Surgery with Preoperative Ventriculo - Peritoneal (V-P) Shunt in Children

CTH Secondary to Paediatric Posterior Fossa Tumour and Post-operative Paediatric Cerebellar Mutism Syndrome: A Retrospective Study in a Tertiary Care Centre

CTH Secondary to Paediatric Posterior Fossa Tumour and Post-operative Paediatric Cerebellar Mutism Syndrome: A Retrospective Study in a Tertiary Care Centre

Endoscopic Third Ventriculostomy: long term results

Objective: Hydrocephalus is a major cause of morbidity in the pediatric population, with potentially severe consequences if left untreated hydrocephalus.&#x0D; Endoscopic third ventriculostomy (ETV) has become the method of choice in the treatment of obstructive hydrocephalus. However, age, ventricular anatomy, and etiology could determine success rates (SR) of ETV. The aim of this study was to identify putative factors that could influence the outcome of ETV in children.&#x0D; Methods: Clinical data of 148 consecutive patients under 18 years of age who underwent 150 consecutive ETVs from January 2000 to January 2019 were reviewed. Data were analyzed with regards to clinical and radiological SR. The actual long-term SR was compared to that predicted by the ETV Success Score (ETVSS) model.&#x0D; Results/Discussion: The study group included 63 males (43%) and 85 females (57%) ranging in age from 11 days to 18 years (mean age of, 6.17 ± 1.02 years; median age 4.5 years) at surgery. Concerning the etiology of hydrocephalus, tumors and aqueductal stenosis (AS) were the most frequently observed, with each occurring in 43 cases (29%), followed by malformations in 31 (21%), cystic lesions in 7 (5%) and other etiologies in 67 patients (16%). The overall SR at the first ETV attempt was 80% (118/148), compared to 74.8% (variance 14.35, 95% CI 69.37–78.22) predicted by the ETVSS. Regarding age, SR was 58% in patients under 6 months of age, 65% in children between 6 months and 1 year, and 86% in children older than 1 year. SR for AS and hydrocephalus associated with posterior fossa tumors were 88 and 90%, respectively. Unsatisfactory results were related to previous intraventricular hemorrhage and infection. The overall complication rate in this series was 13%.&#x0D; The lower SR after ETV in young children may be explained by the poor CSF reabsorption capacity of newborn infants due to immaturity of the arachnoid granulations;&#x0D; Univariate and multivariate analysis showed in our series that both the etiology of hydrocephalus and patient´s age group were relevant factors predicting success.&#x0D; A literature review showed that SR in children under 6 months of age ranged from 32% to 45%, and in children older than one year it ranged from 56% to 71%. A few studies have analyzed the postoperative course and SR after a period of 3 years.&#x0D; Conclusion: ETV is safe and effective in children. In this series, the age of the patient and etiology of hydrocephalus were related to SR. Also, the ETVSS was accurate to predict outcome. Intraventricular hemorrhage, previous CNS infection, myelomeningocele, prematurity and recurrent shunt revisions have been associated with high failure rates of ETV in all age groups, particularly in infants under 6 months of age. In a long-term follow-up, surgical experience was statistically significant in reducing complications.

The long-term impact of irradiation on functional connectivity in brain circuits involved in memory processes after pediatric posterior fossa tumor

PurposeMemory is one of the main specific cognitive domains impaired with attention and processing speed after a pediatric brain tumor. This work explored the long-term impact of radiotherapy in children with posterior fossa tumor (PFT) on brain connectivity in neural circuits involved in memory using resting-state functional magnetic resonance imaging (rs-fMRI). MethodsA total of 20 irradiated and 15 non-irradiated PFT survivors, and 21 healthy controls, prospectively included in the IMPALA study (NCT04324450), performed memory tests assessing episodic, procedural, and working memories and were subjected to an rs-fMRI. We manually contoured main structures involved in memory to explore connectivity at rest in a seed-to-voxel analysis. The groups were compared and differences in connectivity were correlated with behavioral scores and irradiation doses. ResultsThe performance of all mnesic tasks was lower in PFT survivors with a greater alteration in working and episodic memory in irradiated patients. Irradiated survivors had atypical connectivities in all memory circuits compared to controls and in cortico-caudate and cortico-cerebellar circuits compared to non-irradiated survivors. Non-irradiated survivors had only atypical connectivities in the cortico-cerebellar circuits compared to controls. In irradiated survivors, atypical connectivities in cortico-hippocampal circuits were linked with episodic memory scores and dose of irradiation to the left hippocampus and in cortico-striatal circuits with procedural memory scores and dose of irradiation to the striatum. ConclusionThe results of this study highlight that irradiation has a long-term impact on brain connectivity in brain circuits involved in memory after pediatric PFT with a specific radiation-dose effect in supratentorial structures.

Comprehensive Review of Primary Posterior Fossa Tumors in Children

Comprehensive Review of Primary Posterior Fossa Tumors in Children