Conservative management of presumed low-grade gliomas in the asymptomatic pediatric population

Surgical Treatment of Pediatric Incidentally Found Brain Tumors: A Single-Center Experience

There remains much debate about the correct management of incidentally found brain tumors in the pediatric population. This study aimed to evaluate the efficacy and safety of surgical treatment of incidentally found pediatric brain tumors. A retrospective analysis of pediatric patients who underwent surgical resection of incidentally found brain tumors between January 2010 and April 2016 was performed. A total of seven patients were included. The median age at the time of diagnosis was 9.7 years. The reasons for performing neuroimaging were as follows: impeded speech development (n = 2), shunt control (n = 1), paranasal sinuses control (n = 1), behavior changes (n = 1), head trauma (n = 1), and preterm birth (n = 1). Five patients underwent gross total tumor resection (71.4%), while subtotal resection was performed in two patients (28.6%). There was no surgery-related morbidity. Patients were followed up for a mean of 79 months. One patient with atypical neurocytoma experienced tumor recurrence 45 months following primary resection. All patients remained neurologically intact. The majority of pediatric incidentally found brain tumors were histologically benign. Surgery remains a safe therapeutic approach associated with favorable long-term outcomes. Considering the expected long lifetime of pediatric patients, as well as the psychological burden associated with having a brain tumor as a child, surgical resection can be considered an initial approach.

Supratentorial Pediatric Midline Tumors and Tumor-like Lesions: Clinical Spectrum, Natural History and Treatment Options

Childhood Central Nervous System tumors account for 25% of all pediatric tumors. Large availability and broadening of indications to imaging has made incidental findings more common. Among these, midline lesions have different clinical relevance depending on their intrinsic pattern of behaviour and on their specific location. In this narrative review we describe the natural history and treatment options of midline lesions in children.

Pediatric thalamic incidentalomas: an international retrospective multicenter study

OBJECTIVE

Widespread use of modern neuroimaging has led to a surge in diagnosing pediatric brain incidentalomas. Thalamic lesions have unique characteristics such as deep location, surgical complexity, and proximity to eloquent neuronal structures. Currently, the natural course of incidental thalamic lesions is unknown. Therefore, the authors present their experience in treating such lesions.

METHODS

A retrospective, international multicenter study was carried out in 8 tertiary pediatric centers from 5 countries. Patients were included if they had an incidental thalamic lesion suspected of being a tumor and were diagnosed before the age of 20 years. Treatment strategy, imaging characteristics, pathology, and the outcome of operated and unoperated cases were analyzed.

RESULTS

Overall, 58 children (23 females and 35 males) with a mean age of 10.8 ± 4.0 years were included. The two most common indications for imaging were nonspecific reasons (n = 19; e.g., research and developmental delay) and headache unrelated to small thalamic lesions (n = 14). Eleven patients (19%) underwent early surgery and 47 were followed, of whom 10 underwent surgery due to radiological changes at a mean of 11.4 ± 9.5 months after diagnosis. Of the 21 patients who underwent surgery, 9 patients underwent resection and 12 underwent biopsy. The two most frequent pathologies were pilocytic astrocytoma and WHO grade II astrocytoma (n = 6 and n = 5, respectively). Three lesions were high-grade gliomas.

CONCLUSIONS

The results of this study indicate that pediatric incidental thalamic lesions include both low- and high-grade tumors. Close and long-term radiological follow-up is warranted in patients who do not undergo immediate surgery, as tumor progression may occur.

Management of incidental brain tumors in children: a systematic review

BACKGROUND

Due to technical advancements and availability of neuroimaging, detection of incidental pediatric brain tumors (IPBT) is growing rapidly. The management of these asymptomatic lesions remains unclear; radiological, pathological, and clinical risk factors for further growth and malignant transformation (MT) are not well defined.

METHODS

We systematically reviewed the literature on the dilemmas and management of IPBT suggestive of a low-grade brain tumor (LGBT). Keyword searches of the PubMed and Medline (NCBI) databases identified studies on IPBT describing the prevalence, neuroimaging, management, or risk of MT through July 2019. References of the identified articles were also reviewed.

RESULTS

A total of 2021 records were screened. Fifty-nine full-text articles were reviewed, and 34 published studies were included. IPBT are diagnosed in 0.2-5.7% of children undergoing brain imaging for various reasons. The accepted approach for management of lesions showing radiological characteristics suggestive of LGBT is radiological follow-up. The rate at which additional intervention is required during follow-up for these apparently low-grade lesions is 9.5%. Nevertheless, the dilemma of early surgical resection or biopsy vs. clinical and radiological follow-up of IPBT is still unresolved. The risk in these cases is missing a transformation to a higher grade tumor. However, MT of pediatric LGBT is very rare, occurring in less than 3% of the cases of proven low-grade gliomas in children. The risk of future MT in pediatric low-grade gliomas seems to be greater in the presence of specific molecular markers such as BRAF V-600E, CDKN2A, and H3F3A K27M.

CONCLUSIONS

The natural history, management, and prognosis of IPBT remain ambiguous. It seems that lesions suggestive of LGBT can initially be followed, since many of these lesions remain stable over time and MT is rare. However, controversy among centers concerning the ideal approach still exists. Further observational and prospective cohort studies, focusing on potential clinical and radiological characteristics or risk factors suggestive of high-grade tumors, tumor progress, or MT of IPBT, are needed.

Low-grade astrocytoma in the setting of a developmental venous anomaly

Developmental venous anomalies (DVAs) are the most common type of cerebrovascular malformation and are considered benign. There are a few literature studies associating DVA with brain tumors, suggesting a possible underlying predisposition in these patients for tumor neogenesis. We report a 7-year-old female with a complex DVA who developed a low-grade astrocytoma in the opposite hemisphere. With analysis of a comprehensive solid tumor panel and imaging, we describe the possible association of an underlying susceptibility to neoplastic growth in the presence of a vascular malformation.

Incidence of high grade gliomas presenting as radiographically non-enhancing lesions: experience in 111 surgically treated non-enhancing gliomas with tissue diagnosis

PURPOSE

Although non-enhancing lesions suspicious for glioma are usually assumed to be low grade glioma (LGG), some high grade glioma (HGG) do not enhance, which may lead to a delay in biopsy and/or resection, diagnosis, and treatment initiation. Thus, there is a clear need for a large-sample study that quantifies the rate of malignant, non-enhancing gliomas.

METHODS

We retrospectively reviewed our series of 561 consecutive surgically treated gliomas with tissue diagnosis, 111 of which were non-enhancing, to determine the prevalence of high-grade histology in radiographically presumed LGG. Relative expression of tumor markers were also reported for non-enhancing lesions to investigate genetic correlates.

RESULTS

We identified 561 surgically treated gliomas with tissue diagnosis from August 2012 to July 2018 and found that 111 patients (19.8%) demonstrated non-enhancing lesions suspicious for glioma on preoperative MRI. Thirty-one (27.9%) of the non-enhancing lesions were classified as HGGs (WHO Grade III or IV). Non-enhancing lesions were four times more likely to be HGG in patients older than 60 years than patients younger than 35 years (41.2% vs. 11.4%, Pearson Chi² p < 0.001). Binomial logistic regression showed a significant inverse effect of age on the presence of IDH mutation in non-enhancing HGGs (p = 0.007).

CONCLUSION

A clinically significant proportion (27.9%) of non-enhancing lesions were found to be HGG on final pathologic diagnosis. Thus, in patients with good functional and health status, especially those older than 60 years, we recommend obtaining tissue diagnosis of all lesions suspected to be glioma, even those that are non-enhancing, to guide diagnosis as well as early initiation of chemotherapy and radiation therapy.

Incidental Brain Tumors in the Pediatric Population: A Systematic Review and Reappraisal of Literature

OBJECTIVES

Management of incidental asymptomatic brain tumors in children is controversial due to lack of clear evidence-based guidelines. We present this systematic review in an attempt to highlight an optimal treatment paradigm.

METHODS

This systematic review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Databases were searched up to August 2019 using the keywords "incidental," "brain tumor," and "pediatric." Our main focus was on brain lesions suspected for neoplasm, diagnosed incidentally on neuroimaging in an otherwise asymptomatic patient <18 years old. Cystic, vascular, and inflammatory brain lesions were excluded.

RESULTS

Fourteen studies comprising 308 patients were included. All cases were diagnosed using magnetic resonance imaging. The most common indications for imaging were headache (93; 30%) and trauma (72; 23%). Lesion distribution was supratentorial (179; 58%), infratentorial (121; 40%), and intraventricular (8; 3%). Of 308 cases, 243 (79%) were managed with neuroradiological surveillance and 57 (19%) by upfront surgical excision. Of those managed conservatively, 177 (73%) remained stable within a mean follow-up of 30 months, 54 (22%) progressed, and 12 (5%) spontaneously regressed. Meanwhile, upfront excision achieved complete remission in all 57 cases over a mean follow-up of 68.3 months.

CONCLUSION

A small body of evidence has emerged, highlighting the marked heterogeneity and contradictory results between the available studies, limiting our ability to draw solid conclusions. At this point, the decision between surgery and "watchful waiting" should be tailored on an individual patient basis depending on suspicion of malignancy, clinical or radiologic progression, and parental preference.

Pediatric posterior fossa incidentalomas

PURPOSE

Pediatric brain incidentalomas are increasingly being diagnosed. As the posterior fossa (PF) is the location of most brain tumors in children, lesions of this region are of special interest. Currently, the natural history of incidental lesions in the PF is unknown. We present our experience treating such lesions.

METHODS

A retrospective study was carried out in two large tertiary pediatric centers. Patients were included if they had an incidental PF lesion suspected of being a tumor, and diagnosed before the age of 20 years. We analyzed treatment strategy, pathology, and outcome of operated and non-operated cases.

RESULTS

Seventy children (31 females) with a mean age of 8.4 ± 6.1 years were included. The three most common indications for imaging were headaches (16, assumed to be unrelated to the lesions), workup of unrelated conditions (14), and unspecified reasons (14). Twenty-seven patients (39%) were operated immediately, and 43 followed, of which 12 were eventually operated due to radiological changes, 28.9 ± 16.2 months after diagnosis. The most commonly found pathology was pilocytic astrocytomas (21 of 39 operated cases). Almost 10% were found to be malignant tumors including medulloblastomas (5) and ATRT (1).

CONCLUSION

Incidental PF lesions in children include both benign and malignant tumors. While certain lesions may be followed, others may require surgical treatment. Specific treatment decisions are based on initial radiological appearance, change in radiological characteristics over time, location, and evolving symptoms. The surgical risks must be balanced vis-à-vis the risk of missing a high-grade tumor and the very rare risk of malignant transformation.

Interval brain imaging for adults with cerebral glioma

BACKGROUND

Clinical practice guidelines suggest that magnetic resonance imaging (MRI) of the brain should be performed at certain time points or intervals distant from diagnosis (interval or surveillance imaging) of cerebral glioma, to monitor or follow up the disease; it is not known, however, whether these imaging strategies lead to better outcomes among patients than triggered imaging in response to new or worsening symptoms.

OBJECTIVES

To determine the effect of different imaging strategies (in particular, pre-specified interval or surveillance imaging, and symptomatic or triggered imaging) on health and economic outcomes for adults with glioma (grades 2 to 4) in the brain.

SEARCH METHODS

The Cochrane Gynaecological, Neuro-oncology and Orphan Cancers (CGNOC) Group Information Specialist searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase up to 18 June 2019 and the NHS Economic Evaluation Database (EED) up to December 2014 (database closure).

SELECTION CRITERIA

We included randomised controlled trials, non-randomised controlled trials, and controlled before-after studies with concurrent comparison groups comparing the effect of different imaging strategies on survival and other health outcomes in adults with cerebral glioma; and full economic evaluations (cost-effectiveness analyses, cost-utility analyses and cost-benefit analyses) conducted alongside any study design, and any model-based economic evaluations on pre- and post-treatment imaging in adults with cerebral glioma.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane review methodology with two authors independently performing study selection and data collection, and resolving disagreements through discussion. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included one retrospective, single-institution study that compared post-operative imaging within 48 hours (early post-operative imaging) with no early post-operative imaging among 125 people who had surgery for glioblastoma (GBM: World Health Organization (WHO) grade 4 glioma). Most patients in the study underwent maximal surgical resection followed by combined radiotherapy and temozolomide treatment. Although patient characteristics in the study arms were comparable, the study was at high risk of bias overall. Evidence from this study suggested little or no difference between early and no early post-operative imaging with respect to overall survival (deaths) at one year after diagnosis of GBM (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.61 to 1.21; 48% vs 55% died, respectively; very low certainty evidence) and little or no difference in overall survival (deaths) at two years after diagnosis of GBM (RR 1.06, 95% CI 0.91 to 1.25; 86% vs 81% died, respectively; very low certainty evidence). No other review outcomes were reported. We found no evidence on the effectiveness of other imaging schedules. In addition, we identified no relevant economic evaluations assessing the efficiency of the different imaging strategies.

AUTHORS' CONCLUSIONS

The effect of different imaging strategies on survival and other health outcomes remains largely unknown. Existing imaging schedules in glioma seem to be pragmatic rather than evidence-based. The limited evidence suggesting that early post-operative brain imaging among GBM patients who will receive combined chemoradiation treatment may make little or no difference to survival needs to be further researched, particularly as early post-operative imaging also serves as a quality control measure that may lead to early re-operation if residual tumour is identified. Mathematical modelling of a large glioma patient database could help to distinguish the optimal timing of surveillance imaging for different types of glioma, with stratification of patients facilitated by assessment of individual tumour growth rates, molecular biomarkers and other prognostic factors. In addition, paediatric glioma study designs could be used to inform future research of imaging strategies among adults with glioma.

Incidental brain tumors in children: an international neurosurgical, oncological survey

PURPOSE

Incidental pediatric brain tumors (IPBT) are increasingly being diagnosed. Currently, there is no consensus regarding the need and timing of their treatment. In the current study, we identify trends among pediatric neurosurgeons and oncologists with regard to IPBT management and approval of growth hormone replacement therapy (GHRT).

METHODS

A questionnaire presenting six different cases of IPBT was emailed to all members of several leading societies in pediatric neurosurgery and oncology. Collected data included basic information concerning the responders (profession, experience, continent of practice), as well as responses to multiple questions regarding treatment of the lesion, permission to supply GHRT, and free text for comments.

RESULTS

One hundred forty-three responses were eligible for analysis (92 neurosurgeons, 51 oncologists, from a total of 6 continents). Initial recommendations for each case were heterogeneous. However, a few consistent trends were identified: Lesions that were stable over time lead to a common shift in treatment recommendation to a more conservative one. Growing lesions were commonly treated more aggressively. Neither profession nor experience had a consistent impact on recommendations.

CONCLUSIONS

Management recommendations for IPBT varied among the responders and seem to be influenced by many factors. However, stable lesions lead to a shift in management towards a "watch and wait" approach, while in growing lesions responders tended towards a "biopsy" or "resection" approach. This highlights the need for better understanding of the natural course of incidental brain tumors in children, as well as evaluating the potential risk for malignant transformation.

Paediatric gliomas: diagnosis, molecular biology and management

Paediatric gliomas represent the most common brain tumour in children. Early diagnosis and treatment greatly improve survival. Histological grade is the most significant classification system affecting treatment planning and prognosis. Paediatric gliomas depend on pathways and genes responsible for mitotic activity and cell proliferation as well as angiogenesis (MAPK, VEGF, EFGR pathways). Symptoms such as focal neurologic deficit or seizures can facilitate diagnosis, but they are not always present and therefore diagnosis is occasionally delayed. Imaging has adequate diagnostic accuracy (surpassing 90%), and novel imaging techniques such as MR spectroscopy and PET increase only slightly this percentage. Low grade gliomas (LGG) can be approached conservatively but most authors suggest surgical excision. High grade gliomas (HGG) are always operated with exception of specific contradictions including butterfly or extensive dominant hemisphere gliomas. Surgical excision is universally followed by radiotherapy and chemotherapy, which slightly increase survival. Inoperable cases can be managed with or without radiosurgery depending on location and size, with adjunctive use of radiotherapy and chemotherapy. Surgical excision must be aggressive and gross total resection (GTR) should be attempted, if possible, since it can triple survival. Radiosurgery is effective on smaller tumours of <2 cm2. Surgical excision is always the treatment of choice, but glioma recurrences, and residual tumours in non-critical locations are candidates for radiosurgery especially if tumour volume is low. Management of recurrences includes surgery, radiosurgery and chemoradiotherapy and it should be individualized according to location and size. In combination with molecular targeted therapeutic schemes, glioma management will be immensely improved in the next years.

Malignant transformation of a conservatively managed incidental childhood cerebral mass lesion: controversy regarding management paradigm

BACKGROUND

Incidental findings on neuroimaging in the pediatric population are an emerging treatment challenge. Treatment options for these incidental childhood brain mass lesions, which radiologically may be assumed to be low-grade gliomas (LGG), vary, ranging from careful conservative "wait and scan" treatment to surgical biopsy, gross total resection, and upfront radiation and/or chemotherapy. As malignant transformation of LGG in children is extremely rare, some series advocate careful conservative management of these lesions; however, universal treatment protocols are not totally agreed upon.

ILLUSTRATIVE CASE

We present the case of a 10-year-old boy with a fronto-basal incidental cerebral mass lesion, suspected to be a low-grade glial neoplasm. Initially, magnetic resonance imaging (MRI) was done to rule out a pathology causing his growth to be delayed. A treatment with growth hormone was initiated. After close clinical and radiological follow-up of this asymptomatic lesion for 6 years, a minimal growth of the lesion was seen, which we decided to continue following. After 7 years, a clear growth with new contrast enhancement was seen on routine MRI. At this point, the lesion was surgically resected. The diagnosis was, surprisingly, glioblastoma multiforme (WHO grade IV, BRAF V-600E mutation).

DISCUSSION

Malignant transformation of LGGs in children is a very rare phenomenon. This is to our knowledge the first well-documented case describing malignant transformation of a suspected benign pediatric cerebral mass lesion, which did not undergo radiation, in a patient without a cancer predisposition syndrome (e.g., neurofibromatosis), with the transformation occurring after such a long follow-up period. The management of these lesions is still controversial. Unfortunately, radiological risk factors for malignant transformation of such lesions in the pediatric age group are lacking.

CONCLUSION

Conservative treatment of incidental cerebral mass lesions in children seems a valid option. These lesions should probably be followed indefinitely, while carefully watching for changes in imaging characteristics.

Neurosurgical tools to extend tumor resection in pediatric hemispheric low-grade gliomas: iMRI

INTRODUCTION

The treatment of low-grade gliomas (LGGs) in pediatric age is still controversial. However, most authors report longer life expectancy in case of completely removed cerebral gliomas. Intraoperative magnetic resonance imaging (iMRI) is increasingly utilized in the surgical management of intra-axial tumor in adults following the demonstration of its effectiveness. In this article, we analyze the management of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population.

METHODS

We performed review of the literature regarding the treatment of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population. Some exemplary cases are also described.

RESULTS

Intraoperative MRI allowed extension of tumor resection after the depiction of residual tumor at the intraoperative imaging control from 21 to 52 % of the cases in the published series. Moreover, the early reoperation rate was significantly lower when compared with the population treated without this tool (0 % vs 7-14 %). Some technical difficulties have been described in literature regarding the use of iMRI in the pediatric population especially for positioning due to the structure of the headrest coil designed for adult patients.

CONCLUSION

The analysis of the literature and our own experience with iMRI in children indicates significant advantages in the resection of LGG offered by the technique. All these advantages are obtained without elongation of the surgical times or increased risk for complications, namely infection. The main limit for a wider diffusion of iMRI for the pediatric neurosurgical center is the cost required, for acquisition of the system, especially for high-field magnet, and the environmental and organizational changes necessary for its use.

Congenital cystic eye associated with a low-grade cerebellar lesion that spontaneously regressed

Background

Congenital cystic eye is an exceedingly rare ocular malformative disease, originated from the failure in the invagination of the optic vesicle during the fetal period and it can be associated with other ocular and non-ocular abnormalities. Diagnosis is based on clinical, radiological and histological features.

Case presentation

We report a case of a congenital cystic eye associated with a cerebellar lesion accidentally detected at magnetic resonance imaging. Biopsy of the mass has not been performed due to parental rejection. Based on radiologic features and absence of clinical signs, a low-grade glioma diagnosis was hypothesized, but histological characterization was not obtained. Follow-up neuro-imaging 6 months after diagnosis showed that intracranial lesion spontaneously regressed without any treatment.

Conclusion

Our report stresses the importance of early MRI in children with ocular malformations, in order to detect associated intracranial defects, also of non-malformative origin. Additionally, we debate the clinic-radiological features of the intracranial lesions that could allow a wait-and-see policy. We also recommend a strict clinical and neuro-imaging follow-up for these lesions. Finally, biological mechanisms at the base of spontaneous regression of the brain lesions are discussed.