Infratentorial Brain Tumors Research Articles

Postoperative epidural hematoma as a rare complication after intracranial tumor resection: a case series report and causes analysis

BackgroundTo review the treatment and the causes of postoperative epidural hematoma (PEDH) after intracranial tumor resection.MethodA retrospective case study was conducted to examine a series of patients who developed PEDH as a complication following intracranial tumor resection between January 2016 and June 2021. The study collected data from hospital charts, including clinical status at admission, imaging results, histopathologic findings, surgical management, complications, and outcomes. Causes of PEDH were evaluated through a review of operative notes and discussions with the surgical team.ResultsTwenty-five patients (10 males, 15 females; median age 42 years, range 11–61 years; median medical history 27 months, range 1–96 months) were enrolled in the study. Regarding tumor location, 16 cases exhibited supratentorial brain tumors, 4 cases had infratentorial brain tumors, 2 cases of tumors occurred in the petroclival region, 2 cases in the peritorcular region, and 1 case in the pineal region. Four of these cases were complicated with supratentorial hydrocephalus. The 25 cases in this study were classified into four types based on location. Type 1 refers to EDHs that occur at the adjacent site of the operative field without involvement of the surgical area. Type 2 includes hematomas that occur at the adjacent site of the surgical area and the surgical area. Type 3 includes EDHs that occur in distant areas, and type 4 involves EDHs in the surgical field. The numbers of cases of types 1, 2, 3, and 4 PEDHs were 16, 2, 3, and 4 cases, respectively. Most PEDHs were associated with reduced ICP after craniotomy due to intracranial tumor resection and substantial loss of CSF. All patients achieved satisfactory outcomes after hematoma evacuation.ConclusionThe decrease in ICP resulting from intracranial tumor resection and CSF loss might lead to PEDHs. By employing optimized surgical techniques and meticulous patient management to prevent rapid decreases in ICP and dural detachment, we can potentially lower the incidence of PEDHs. Additionally, prompt evacuation of hematomas can contribute to positive outcomes.

14 The Impact of Socioeconomic Status (SES) on Phonemic Fluency in Patients with Pediatric Brain Tumor (PBT)

Objective:Phonemic fluency, an important cognitive skill for everyday functioning, has been shown to decline in comparison to same-aged peers following pediatric cancer diagnosis and treatment, despite intact semantic fluency. More generally, socioeconomic status (SES) has recently been shown to be one of the strongest predictors of neuropsychological outcomes among pediatric oncology patients, with lower SES predicting worse intellectual and academic functioning. However, the association between SES and phonemic fluency within this population has yet to be explored. The main objective of this project was to determine whether SES (specifically estimated household income) significantly predicts phonemic fluency performance among patients with PBT, and it was hypothesized that higher SES would be associated with better phonemic fluency outcomes.Participants and Methods:136 participants with PBT ages 7-20 (x=14.15 years, SD=3.87), were administered phonemic fluency trials (either from the NEPSY - Second Edition or Delis-Kaplan Executive Function System, with no significant differences in performance between measures). The sample was 58.8% male and half Latino (50.0%), followed by Caucasian (30.1%), Asian American (7.4%), Black (6.6%), and Other (5.9%) ethnicity. All patients identified English as their primary and preferred language regardless of predominant household language, reducing the potential confounding impact of language. Given documented associations between PBT and lower intelligence following diagnosis and treatment, estimated intellectual functioning was included in the first block of hierarchical regression to isolate and further elucidate the potential contributing influence of SES on phonemic fluency. Median household income for specific neighborhoods was used as a proxy for SES, while Wechsler Matrix Reasoning (MR) was used as an estimate of general intellectual functioning given the high correlation between MR and full scale IQ.Results:Consistent with prior literature, phonemic fluency was lower than normative age expectations [t(135)=-3.653, p=.0002], though still within the average range clinically (x=8.93). As hypothesized, SES was positively correlated with phonemic fluency [r(136)=.219, p=.005]. Furthermore, SES significantly predicted phonemic fluency performance above and beyond estimated intelligence, accounting for a significant increase in variance (p=.020). Post-hoc analyses also revealed poorer phonemic fluency among participants with infratentorial brain tumors as compared to supratentorial brain tumors after controlling for SES, t(108)=-1.748, p=.042.Conclusions:Consistent with the known impact of SES on neuropsychological late effects among patients with pediatric cancer, phonemic fluency was positively correlated with SES among participants with PBT above and beyond estimated intelligence, suggesting the distinct role of SES on rapid verbal retrieval within this population. This has important implications for identifying patients at higher risk, helping to ensure timely provision of services and supports. Poorer phonemic fluency was also noted among patients with infratentorial (vs. supratentorial) brain tumors after controlling for SES, which may influence studies combining tumor location as the vast majority of PBTs are infratentorial. This supports prior literature demonstrating the need for increased cerebellar activation during phonemic (vs. semantic) retrieval. Additional research is needed to further explore these findings.

To Demonstrate Challenges in Treating Infratentorial Brain Tumors in Pediatrics at the Children’s Hospital and Institute of Child Health, Lahore

Objective: To demonstrate challenges in treating infratentorial Brain tumors in pediatrics at The Children’s Hospital and Institute of Child Health, Lahore Methodology: This Descriptive observational study was done at the Department of Pediatric Hematology & Oncology at CH&UCH Lahore from August 2021 to February 2022. Sixty-four newly diagnosed patients of infra-tentorial tumors were enrolled by using non-probability, consecutive sampling technique. Main variables of study were age, parents education, socioeconomic status, traveling distance, TLS, stagging workup, Histopathology, Treatment, and Outcome . SPSS version 23.1 was used for data analysis. Test of significance was applied taking p value ≤0.05 as significant value. Results: In this study, the mean age of children was 7.14 ± 3.76 years. Out of 64 children, 35 (54.7%) were males and 29 (45.3%) females Forty three (67%) patients belong to rural area and 21 (32%) from urban area. In our study population, Father of 24 (37.5%) patients and mother of 38 (59.37%) patients never attended school. Fifty six (87.5%) patients belong to low income socioeconomic status while 8(12.5%) patients from middle income status. Thirty four (53.12%) patients had a travelled for more than 200KM. Lag time 1 (patient interval) was <2 weeks in 43 (67.2%) cases, and 2-4 weeks in 20 (31.3%) cases. Lag time 2 (referred interval) was noted as <1 Month in 19 (29.7%) cases, and <2 Months in 26 (40.6%) cases. Lag time 3 (treatment interval) was noted in <1 Month in 2 (3.1%) cases, and <2 Months in 6 (9.4%) cases, but in 48 (75.0%) cases lag time 3 was not applicable. Out of 64 cases, cure with Gross Total Resection was noted in 5 (7.8%) cases, residual tumor in 21 (32.8%) and palliation in 37 (57.8%) cases. Practical implication: The aim was to demonstrate all the challenges in treating Infratentorial tumors and start awareness in the doctor community specially GPs for proper and timely reffral,aware families about the danger signs and symptoms that could be brain tumor. Conclusion: Advanced disease presentation is common, infra tentorial brain tumors are always challenging and has the least favorable outcomes amongst all pediatric tumors. Delayed diagnosis due to cultural and financial barriers and lack of care at primary health care level and poor referral to oncology units owing to deficient health care system are the major contributory challenges for management and poor outcomes. Keywords: lag time, infra-tentorial tumors, challenges, Pediatrics

Infra-tentorial brain tumor subtypes in children and adults\u2014surgical outcome in an ethnic population with a single regional tertiary center

BackgroundTo analyze clinically and radiologically the surgical outcome like residual disease, progression of disease, recurrence, disabilities, event-free survival (EFS), and mortality of different infra-tentorial tumor subtypes in children and adults of a strictly non-migratory and ethnic population.MethodsThe 410 histologically proved, out of 589, infra-tentorial brain tumor patients were analyzed clinically and by the imaging post-surgically in a single tertiary center for an ethnic region. In this analytico-observational study, retrospectively postoperative records of 589 infra-tentorial brain tumors from November 1998 to December 2018 (20 years) were retrieved, scrutinized, and compiled. The post-operative clinic-radiological records of 410 patients with proved histopathological examination results were included. Statistical law of variance was applied where-ever necessary.ResultsThe 63.2% of the all 410 operated infra-tentorial brain tumors were males while females predominated in meningiomas and pineoblastomas. About 31.7% infra-tentorial tumors were children (below 18 years). About 54.1% cases were histologically malignant. The residual tumors comprised 40.2% and symptoms of disease-progression occurred in 10.9%. The tumor recurrence occurred in 14.3% while 6.0% patients developed severe disability. The overall mortality was 11.4% but 18.9% in malignant tumors. The event-free survival (EFS) for all the patients was 66.0%, patients with malignancies had 47.7% and benign group had 87.7%.ConclusionThe study, surgical outcome of infra-tentorial brain tumor subtypes in children and adults (approx. 1/3rd of patients being children), conducted in a tertiary center at a remote land-locked location with non-migratory ethnic population as its catchment area, has a significant epidemiological value for the community and the region.

Quantifying the Risk and Dosimetric Variables of Symptomatic Brainstem Injury After Proton Beam Radiation in Pediatric Brain Tumors

Brainstem toxicity after radiation is a devastating complication and a particular concern with proton radiation (RT), given the biological differences and range uncertainties at the distal edge of proton beam. Data from St. Jude's found a 3.7% risk of brainstem necrosis after photon-based RT, while the incidence with protons ranges from 0.7% - 31% across studies. We investigated the incidence and clinical correlates of brainstem injury in pediatric brain tumors treated with proton therapy.All patients < 18 years with infratentorial brain and pineal tumors, treated with proton beam RT at our institution from 2007 - 2019, with a brainstem Dmean of > 30 Gy and/or Dmax > 50.4 Gy were included. We excluded patients with primary brainstem tumors. Symptomatic brainstem injury (SBI) was defined as any new or progressive cranial neuropathy, ataxia, dysmetria and/or motor weakness with corresponding radiographic abnormality within the brainstem and was graded per the NCI Common Terminology Criteria for Adverse Events v5.0 (Grade 2: moderate symptoms, corticosteroids indicated; Grade 3: severe symptoms, medical intervention indicated; Grade 4: life-threatening; urgent intervention; and Grade 5: death).A total of 595 patients were reviewed and 362 (medulloblastoma = 209, ependymoma = 86, ATRT = 43, pineoblastoma = 9, others = 15) met our inclusion criteria. Median age at RT was 5 years (range 0.7 - 17.9 years) and median prescribed RT dose was 54 CGyE (range 39.6 - 59.4 CGyE). Median follow up was 40 months (range 1 - 152). Ten patients (2.7%) developed SBI, at a median of 4 months after RT (range 1-6). Grades 2,3,4 and 5 brainstem injuries were seen in 3, 4, 2 and 1 patient respectively. Mean brainstem Dmax in SBI and non-SBI patients was 55.9 Gy and 54.8 Gy (P = 0.30), while the mean Dmean was 43.3 Gy and 43.2 Gy (P = 0.48) respectively. Most common symptoms of SBI were ataxia, slurred speech, 6th cranial nerve palsy and bulbar palsy. All SBI patients required steroids for 1-5 months, while grade 3-5 injuries were also treated with bevacizumab and/or hyperbaric oxygen therapy. Asymptomatic imaging changes within brainstem were seen in 47 patients (13%) at a median of 4 months after RT, most common findings being increased T2 flair, focal enhancement and encephalomalacia. In 2014, our institution started using strict brainstem dose constraints (Dmax ≤ 57 Gy, Dmean ≤ 52.4 Gy and V54 ≤ 10%). The incidence of SBI has decreased from 4.2% (2007-2013) to 0.7% (2014-2019) (P = 0.047) while asymptomatic imaging changes remain similar (11.6% vs 15.1%, P = 0.33). Patients with SBI had a higher V45, V50-52 and D15 -D50; while the Dmax, Dmean, V53-60 and D1- D10 were similar.Our results suggest that there is a low risk of SBI after proton therapy for pediatric brain tumors. A lower incidence of SBI was seen after the use of strict brainstem dose constraints. Volumetric doses to brainstem may play a significant role in determining the risk of SBI and developing a dose response nomogram is warranted.

The Role of PET in Supratentorial and Infratentorial Pediatric Brain Tumors.

Objective: This review aims to provide a summary of the clinical indications and limitations of PET imaging with different radiotracers, including 18F-fluorodeoxyglucose (18F-FDG) and other radiopharmaceuticals, in pediatric neuro-oncology, discussing both supratentorial and infratentorial tumors, based on recent literature (from 2010 to present). Methods: A literature search of the PubMed/MEDLINE database was carried out searching for articles on the use of PET in pediatric brain tumors. The search was updated until December 2020 and limited to original studies published in English after 1 January 2010. Results: 18F-FDG PET continues to be successfully employed in different settings in pediatric neuro-oncology, including diagnosis, grading and delineation of the target for stereotactic biopsy, estimation of prognosis, evaluation of recurrence, treatment planning and assessment of treatment response. Nevertheless, non-18F-FDG tracers, especially amino acid analogues seem to show a better performance in each clinical setting. Conclusions: PET imaging adds important information in the diagnostic work-up of pediatric brain tumors. International or national multicentric studies are encouraged in order to collect larger amount of data.

İntratümöral Ve Peritümöral ADC(Apperent Diffusion Coefficient) Değerlerinin Pediatrik Beyin Tümörlerinin Tanısında Önemi Var Mıdır?

INTRODUCTION: The motion of water particles within biological tissues, which is called random Brownian motion, is detected at the microscopic level by Diffusion-Weighted Imaging (DWI) sequence of Magnetic Resonance Image technique. The Apparent Diffusion Coefficient (ADC) calculated on DWI has been used for tumor diagnosis and grading. The purpose of this study was to evaluate of ADC values in the differential diagnosis of supratentorial and infratentorial pediatric brain tumors and to reveal the difference of peritumoral ADC measurements of pediatric patients from adult patients. METHODS: All of the 56 pediatric patients included in this retrospective study had lesions &gt;1 cm in diameter on magnetic resonance image and all of the diagnosies were confirmed by histopathology. Intratumoral and peritumoral ADC values and ratios were measured in diffusion weighted Magnetic Resonance Image. RESULTS: The 58.9% (n=33) of these tumors were supratentorial and 41.1% (n=23) were infratentorial. ADC values and ADC ratios were significantly lower in high-grade tumors than low-grade tumors (p&lt;0.05). Peritumoral ADC values in high-grade tumors were lower than low grade tumors (p&lt;0.05). The cut-off value of the ADC ratio between these two groups was 1 and the ADC cut-off value was 1.1*10-3 mm2/s. DISCUSSION AND CONCLUSION: In the differentiation of low and high-grade pediatric brain tumors, cut-off values of 1.1*10_3mm2/s for ADC Value and 1.0 for ADC Ratio may be useful. Although, peritumoral ADC values differ in children compared to the adult group, both intratumoral and peritumoral ADC values can help for grading pediatric brain tumors.

Abstract 4430: Simulating delivery of TTFields to the infratentorium in patients with brainstem gliomas

Abstract Purpose/Objective(s): TTFields are FDA-approved for the treatment of recurrent and newly diagnosed Glioblastoma (GBM) in the supratentorial brain. The EF-14 trial showed that combining TTFields with adjuvant chemo-radiation leads to a significant increase in overall survival compared to adjuvant chemo-radiation alone. High-grade gliomas also occur in the infratentorium and brainstem of pediatric and adult patients. Brainstem gliomas have a median survival of 9 to 11 months, necessitating the exploration of novel treatment combinations, such as delivering TTFields to the infratentorial brain. We recently showed in a simulation-based study that TTFields can be successfully delivered to the infratentorium. Effective delivery was achieved by placement of the arrays on the vertex, bilateral posterolateral occiput, and superior-posterior neck; the array placement results in TTFields at therapeutic intensities throughout the brainstem and cerebellum of realistic computational head models. The previous simulation-based study was performed using realistic computational models of healthy individuals; it did not provide detailed insight into field distributions within tumor tissue located in the infratentorium. Here, we aim to expand the results of this previous study, by simulating the delivery of TTFields to the infratentorium of adult and pediatric patients with high-grade brainstem gliomas. Materials/Methods: A realistic computational model was created using MRI data of adult and pediatric patients with high-grade brainstem gliomas. Transducer arrays were placed on the model and the delivery of TTFields to the infratentorial brain was then simulated using a commercial numerical solver. The electric field distribution in the supratentorium, infratentorium, and within the tumor were derived from the simulations, and the dose in the tumor analyzed. Results: The distribution of calculated isofield lines demonstrates effective delivery of TTFields to infratentorial brain tumors. Conclusion: Our results provides rationale for clinically investigating the utility of TTFields in treating infratentorial high-grade gliomas. Citation Format: Marigdalia K. Ramirez-Fort, Brittany Cross, Ariel Naveh, Shearwood McClelland III, Melissa Mendez, Roberto Santiago, Sean S. Mahase, Jaime Matta, Ze'ev Bomzon, Christopher S. Lange. Simulating delivery of TTFields to the infratentorium in patients with brainstem gliomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4430.

The Utility of Routine Intensive Care Admission for Patients Undergoing Intracranial Neurosurgical Procedures: A Systematic Review.

Patients who have undergone intracranial neurosurgical procedures have traditionally been admitted to an intensive care unit (ICU) for close postoperative neurological observation. The purpose of this study was to systematically review the evidence for routine ICU admission in patients undergoing intracranial neurosurgical procedures and to evaluate the safety of alternative postoperative pathways. We were interested in identifying studies that examined selected patients who presented for elective, non-emergent intracranial surgery whose postoperative outcomes were compared as a function of ICU versus non-ICU admission. A systematic review was performed in July 2016 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist of the Medline database. The search strategy was created based on the following key words: "craniotomy," "neurosurgical procedure," and "intensive care unit." The nine articles that satisfied the inclusion criteria yielded a total of 2227 patients. Of these patients, 879 were observed in a non-ICU setting. The most frequent diagnoses were supratentorial brain tumors, followed by patients with cerebrovascular diseases and infratentorial brain tumors. Three percent (30/879) of the patients originally assigned to floor or intermediate care status were transferred to the ICU. The most frequently observed neurological complications leading to ICU transfer were delayed postoperative neurological recovery, seizures, worsening of neurological deficits, hemiparesis, and cranial nerves deficits. Our systematic review demonstrates that routine postoperative ICU admission may not benefit carefully selected patients who have undergone elective intracranial neurosurgical procedures. In addition, limiting routine ICU admission may result in significant cost savings.

Proton radiation for treatment of infratentorial brain tumors in infants and very young children.

10076 Background: Radiation therapy (RT) has historically been delayed for infants with brain tumors due to data suggesting unacceptable toxicity after photon RT. Proton therapy allows definite spa...

The effects of propofol on cerebral perfusion MRI in children

The effects of anesthesia are infrequently considered when interpreting pediatric perfusion magnetic resonance imaging (MRI). The objectives of this study were to test for measurable differences in MR measures of cerebral blood flow (CBF) and cerebral blood volume (CBV) between non-sedated and propofol-sedated children, and to identify influential factors. Supratentorial cortical CBF and CBV measured by dynamic susceptibility contrast perfusion MRI in 37 children (1.8-18 years) treated for infratentorial brain tumors receiving propofol (IV, n = 19) or no sedation (NS, n = 18) were compared between groups and correlated with age, hematocrit (Hct), end-tidal CO₂ (ETCO₂), dose, weight, and history of radiation therapy (RT). The model most predictive of CBF and CBV was identified by multiple linear regression. Anterior cerebral artery (ACA) and middle cerebral artery (MCA) territory CBF were significantly lower, and MCA territory CBV greater (p = 0.03), in IV than NS patients (p = 0.01, 0.04). The usual trend of decreasing CBF with age was reversed with propofol in ACA and MCA territories (r = 0.53, r = 0.47; p < 0.05). ACA and MCA CBF (r = 0.59, 0.49; p < 0.05) and CBV in ACA, MCA, and posterior cerebral artery territories (r = 0.73, 0.80, 0.52; p < 0.05) increased with weight in propofol-sedated children, with no significant additional influence from age, ETCO₂, hematocrit, or RT. In propofol-sedated children, usual age-related decreases in CBF were reversed, and increases in CBF and CBV were weight-dependent, not previously described. Weight-dependent increases in propofol clearance may diminish suppression of CBF and CBV. Prospective study is required to establish anesthetic-specific models of CBF and CBV in children.

Tumor location and neurocognitive impairment in adult survivors of pediatric brain tumors: A report from the St. Jude Lifetime Cohort (SJLIFE).

9531 Background: Follow-up guidelines identify supratentorial tumor location as a risk factor for poor neurocognitive outcomes during childhood; yet few studies have systematically compared long-term cognitive outcomes between adult survivors of childhood infratentorial and supratentorial brain tumors. Methods: Neurocognitive functions were evaluated in 130 adult survivors of pediatric brain tumors (58 supratentorial and 72 infratentorial, mean [SD] current age = 27.4 years [5.2], age at diagnosis = 8.6 years [4.6], and time since diagnosis = 18.8 years [4.8]) participating in the SJLIFE long-term follow-up protocol. Age-adjusted standard scores for measures of intelligence, attention, memory, processing speed, and executive functioning were calculated, with clinical impairment defined as scores &lt;10th percentile. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariable logistic regression models to examine associations between neurocognitive functions and tumor location. Results: As a group, survivors performed below average across multiple neurocognitive domains, including full scale IQ (mean=88.1; SD=18.2), with 34% demonstrating impaired IQ. Survivors of infratentorial tumors were more likely to be impaired on measures of focused attention (OR=2.19, 95% CI=1.03-4.65) and fine motor dexterity (OR=2.62, 95% CI=1.21-5.66) compared to survivors of supratentorial tumors. After adjusting for sex, age at diagnosis, shunt placement and cranial radiation (yes/no), infratentorial tumor location was only associated with reduced performance on a task of visual abstract reasoning (OR=3.76, 95% CI=1.40-10.1). Cranial radiation therapy was independently associated with impaired short-term memory (OR=15.6, 95% CI=1.64-147.8) and processing speed (OR=3.86, 95% CI=1.15-13.0). Conclusions: Tumor location was not associated with neurocognitive impairment after adjusting for treatment exposures. To further delineate potential differences associated with tumor location, future studies will examine factors including radiation dose/volume, extent of surgical resection, and medical complications.

Estudio comparativo del perfil cognitivo de niños en edad escolar con tumores cerebrales infratemporales y supratentoriales que finalizaron el tratamiento médico. Impacto en el funcionamiento escolar y social de la calidad de vida relacionada con salud

Introduction: Due to scientific advances, there is a growing number of pediatric patients surviving cancer. In general, for children who suffer from central nervous system tumors, this survival is associated with secondary adverse effects, such as cognitive deficits. Objetive: To assess cognitive functions and quality of life in children with infratentorial and supratentorial brain tumors. Methods: An analytical observational and prospective study was conducted. The total sample consisted of 51 subjects. The following measurement instruments were used: Wechsler Intelligence Scale for Children, Fourth Edition (WISC IV), Cognitive Assessment System (CAS), Test of Memory and Learning (TOMAL), Graffar Scale; and Peds Quality of Life 4.0 Results: The comparison of the results did not show significant differences between infratentorial and supratentorial tumor location. All patients that were evaluated in the post-cancer-treatment period reveled a similar significant impairment in all the areas studied compared with the level expected in the general population. The most severely affected cognitive functions were processing speed and attention span, mainly on the planning tasks. The findings also show that quality of life at school is severely affected in these children. Conclusions: This is a preliminary study whose results may define a general trend of neurocognitive status, analyzing its impact on quality of life of the study population an posing useful questions for future research.

Infratentorial brain metastases of pediatric non-epithelial malignant tumors: three case reports

Three pediatric patients with infratentorial metastatic non-epithelial malignant brain tumors were successfully treated by radical surgical resection followed by aggressive radiochemotherapy. One patient with neuroblastoma and two with rhabdomyosarcoma were successfully treated by first line multimodal treatments, but developed infratentorial metastasis after several months of remission. All patients revealed intracranial metastases manifesting as rapidly progressing neurological symptoms caused by mass effect in the posterior fossa. Radical surgical resection was performed without morbidity. The patients were then treated by adjuvant radiochemotherapy with or without autologous peripheral blood stem cell transplantation, resulting in complete remission. Two patients developed extracranial recurrences 4 months after the treatments for intracranial metastases. One patient was treated by second high-dose chemotherapy with allogeneic cord blood transplantation, again resulting in complete remission. Another patient was treated by second chemotherapy and maintaining stable disease. The other patient maintained complete remission. All three patients were alive without neurological deficit for 8, 11, and 12 months after diagnosis of brain metastasis. Patients with infratentorial brain metastases of highly malignant pediatric non-epithelial tumors are in a severe clinical state, but still can have longer and useful lives with aggressive multimodal treatments combined with radical surgical resection.

Treatment of posterior fossa tumors in children

The most common posterior fossa tumors in children are medulloblastoma, astrocytoma and ependymoma. Atypical rhabdoid teratoid tumors and brain stem gliomas are relatively rare. As the posterior fossa is a limited space, the tumors presenting in this region cause symptoms early on and require prompt treatment to avoid potential morbidity and mortality. Early detection and diagnosis of these tumors and prompt neurosurgical consultation is crucial in the optimum management of pediatric infratentorial brain tumors. Surgery is the mainstay of treatment, as it provides biopsy and decompression of the tumor. Adjuvant therapy is required in the majority of cases. Recent advances in the field of radiation biology and pharmacology have improved dose and delivery techniques of chemoradiation therapy. In the current era, advances in translational research and molecular genetics have assumed a major role in the pursuit of achieving a ‘cure’ for these potentially malignant tumors.

Late endocrine sequelae after radiotherapy of pediatric brain tumors are independent of tumor location

Irradiation of brain tumors (BT) in children can lead to the loss of pituitary function, predominantly manifesting as deficiencies in GH and ACTH. To assess the incidence and nature of pituitary deficiency in relation to initial tumor location in children after radiotherapy of BT. Twenty survivors (16 males and 4 females) of radiation-treated BT aged 1.4-10.9 (median 3.6) yr at diagnosis were studied, 10 with supratentorial and 10 with infratentorial BT. Radiation doses to the hypothalamus- pituitary (HP) area ranged from 30 to 54 (median 45) Gray. Follow-up was 9.4-16.9 (median 12.2) yr. Basal pituitary hormone levels were measured every 6 months. When growth failure became evident or pituitary deficiency was suspected, provocation tests of the HP axis were performed to assess GH, ACTH, and TSH function. GH deficiency (GHD) developed in 17/20 (85%) children. In 10 patients, it occurred 4 yr after radiotherapy and in 2, 11 and 12 yr after radiotherapy. Six (30%) patients developed secondary hypothyroidism and 4 (20%) developed ACTH deficiency. Precocious puberty occurred in 2 girls. The course of development and the severity of hormone deficiencies were similar for supratentorial and infratentorial tumors. The major hormonal effect of BT irradiation in children is GHD, which may sometimes take more than 10 yr to manifest. We confirm findings by others that ACTH insufficiency occurs less frequently in children than reported for adults. Tumor location has no prognostic significance regarding the loss of HP function.

Infratentorial pediatric brain tumors: the value of new imaging modalities

The correct assessment of the four most frequent infratentorial brain tumors in children (medulloblastoma, ependymoma, pilocytic astrocytoma and infiltrating glioma) has always been problematic. They are known to often resemble one another on conventional magnetic resonance (MR) imaging. We tested the hypothesis whether the combined strength of diffusion-weighted imaging (DWI) and proton MR spectroscopy (MRS) could help differentiate these tumors. Seventeen children with untreated posterior fossa tumors were investigated between January 2005 and January 2006 with conventional MR imaging and combined DWI and MR spectroscopy using a single-voxel technique at short and long echo time (TE) of 30 ms and 135 ms respectively. Apparent diffusion coefficient (ADC) values were retrieved after regions of interest were manually positioned within non necrotic tumor core. Water signal was quantified and metabolite signals were compared and analyzed using linear discriminant analysis. When a combination of ADC values and normalized metabolites was used, all tumors could be discriminated against one other. This could only be achieved when metabolites were normalized using water as an internal standard. They could not be discriminated when using metabolite ratios or ADC values alone, nor could they be differentiated using creatine (Cr) as an internal reference even in combination with ADC values. In conclusion, linear discriminant analysis and multiparametric combination of DWI and MRS, although not replacing histology, fully discriminates the four most frequent posterior fossa tumors in children, but metabolites have to be normalized using water and not Cr signal as an internal reference.

Differential infratentorial brain tumor diagnosis in children

With the exception of the first year of life, infratentorial brain tumors are more frequent in the first decade than tumors in the supratentorial compartment. In particular these are cerebellar low-grade astrocytomas, medulloblastomas, brainstem gliomas and ependymomas of the fourth ventricle. The morphology on MRI and CT and the mode of dissemination permit differential diagnosis in many cases. To allow correct stratification into different treatments in possibly disseminating malignant brain tumors, knowledge of the status of dissemination is essential, and therefore not only cranial but also spinal MRI is indispensable for staging. If the spinal MRI is performed in the immediate postoperative period, knowledge of the normal non-specific purely postoperative changes, often seen as enhancement in the subdural spinal spaces, is necessary in order to avoid misinterpretation as meningial seeding. The differential diagnosis of pediatric infratentorial brain tumors and the morphology of subdural enhancement are illustrated with typical images. The natural history of the most frequent tumors and its importance for treatment decisions is discussed in light of the literature.

Assessment of neuronal tract fibers using three-dimensional anisotropy contrast imaging in patients with infratentorial brain tumors

The purpose of this study was to evaluate neuronal tracts in patients with infratentorial brain tumors using three-dimensional anisotropy contrast (3DAC) imaging technique. Twenty-two patients with infratentorial tumors underwent echo-planar diffusion-weighted imaging (DWI). Gray scale DWIs in each of the three orthogonal diffusion gradients were transformed and color-coded with three primary colors to compose a 3DAC image. Morphological changes of neuronal tracts were assessed. Fine anatomical structures of neuronal tracts were visible on 3DAC images, including pyramidal tract, medial leminscus, superior and middle cerebellar peduncles. Pathological findings of these tracts were categorized as compression or displacement, alteration of fiber directionality, involvement in tumor invasion or perifocal edema, and loss of anisotropy characterized by fading of their own color. Among these, only the loss of anisotropy was correlated with presenting tract-related deficits. The 3DAC imaging is useful to evaluate infratentorial neuronal tracts and to provide useful information to determine surgical strategy in patients with infratentorial brain tumors.

Management of infratentorial brain tumors.

Because 60-70% of brain tumors in children occur in the posterior fossa, the pediatric neurosurgeon must be familiar with the specialized techniques necessary for successful surgery in this region. We discuss the preoperative evaluation, surgical techniques, and postoperative management for children harboring infratentorial brain tumors. Using this approach to treatment, we have had no operative mortalities, a 2% rate of infection, a 15% rate of transient neurologic deficit, and a 5% rate of permanent neurologic deficit.