Management of low-grade gliomas in childhood

Incidental brain tumor findings in children: prevalence, natural history, management, controversies, challenges, and dilemmas

Incidental brain tumor findings in children involve the unexpected discovery of brain lesions during imaging for unrelated reasons. These findings differ significantly from those in adults, requiring a focus on pediatric-specific approaches in neurosurgery, neuroimaging, and neuro-oncology. Understanding the prevalence, progression, and management of these incidentalomas is crucial for informed decision-making, balancing patient welfare with the risks and benefits of intervention. Incidental brain tumors are observed in about 0.04-5.7% of cases, with most suspected low-grade lesions in children showing a benign course, though up to 3% may undergo malignant transformation. Treatment decisions are influenced by factors such as patient age, tumor characteristics, and family anxiety, with conservative management through surveillance often preferred. However, upfront surgery may be considered in cases with low surgical risk. Initial follow-up typically involves a comprehensive MRI after three months, with subsequent scans spaced out if the lesion remains stable. Changes in imaging or symptoms during follow-up could indicate malignant transformation, prompting consideration of surgery or biopsy. Several challenges and controversies persist, including the role of upfront biopsy for molecular profiling, the use of advanced imaging techniques like PET-CT and magnetic resonance spectroscopy, and the implications of the child's age at diagnosis. These issues highlight the need for further research to guide management and improve outcomes in pediatric patients with incidental brain tumor findings.

[Stereotactic irradiation in the complex treatment of patients with intracranial pilocytic astrocytoma]

Complex management of patients with intracranial pilocytic astrocytoma (PA) consists of surgical treatment, drug therapy (mainly in young children) and radiotherapy. For many years, radiotherapy (RT) has been a standard for residual tumors, recurrence or continued growth of PA. Currently, stereotactic radiosurgery and radiotherapy are preferred for PA, because these procedures are characterized by high conformity and selectivity, precise irradiation of tumor with minimal damage to surrounding intact tissues. Stereotaxic approach is very important since PAs are localized near functionally significant and radiosensitive brain structures in most cases. There is significant experience of single-center studies devoted to radiotherapy of patients with PA at the Department of Neuroradiosurgery of the Burdenko Neurosurgery Center. In this research, the authors analyzed the results of stereotactic irradiation of 430 patients with PA for the period from 2005 to 2018.

Treatment with endoscopic transnasal resection of hypothalamic pilocytic astrocytomas: a single-center experience

Backgrounds

Pilocytic astrocytomas (PAs) are World Health Organization (WHO) grade I tumors, which are relatively common, and are benign lesions in children. PAs could originate from the cerebellum, optic pathways, and third ventricular/hypothalamic region. Traditional various transcranial routes are used for hypothalamic PAs (HPAs). However, there are few studies on hypothalamic PAs treated through the endoscopic endonasal approach (EEA). This study reports the preliminary experience of the investigators and results with HPAs via expanded EEAs.

Methods

All patients with HPAs, undergone EEA in our hospital from 2017 to 2019, were retrospectively reviewed. The demographic data, clinical symptoms, complications, skull base reconstruction, prognosis, and endocrinological data were all recorded and analyzed in detail.

Results

Finally, five female patients were enrolled. The average age of patients was 28.6 ± 14.0. All patients had complaints about their menstrual disorder. One patient had severe bilateral visual impairment. Furthermore, only one patient suffered from severe headache due to acute hydrocephalus, although there were four patients with headache or dizziness. Four cases achieved gross-total resection, and one patient achieved subtotal resection. Furthermore, there was visual improvement in one patient (case 5), and postoperative worsening of vision in one patient (case 4). However, only one patient had postoperative intracranial infection. None of the patients experienced a postoperative CSF leak, and in situ bone flap (ISBF) techniques were used for two cases for skull base repair. In particular, ISBF combined with free middle turbinate mucosal flap was used for case 5. After three years of follow-up, three patients are still alive, two patients had no neurological or visual symptoms, or tumor recurrence, and one patient had severe hypothalamic dysfunction. Unfortunately, one patient died of severe postoperative hypothalamus reaction, which presented with coma, high fever, diabetes insipidus, hypernatremia and intracranial infection. The other patient died of recurrent severe pancreatitis at one year after the operation.

Conclusion

Although the data is still very limited and preliminary, EEA provides a direct approach to HPAs with acceptable prognosis in terms of tumor resection, endocrinological and visual outcomes. ISBF technique is safe and reliable for skull base reconstruction.

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.

CNS Tumors in Adolescents and Young Adults: The Need for a Holistic Specialized Approach

CNS tumors are one of the most common causes of cancer-related death in the 15- to 39-year-old age group. The management of adolescents and young adults (AYAs) who are diagnosed with brain tumors presents unique endocrine, developmental, and psychosocial issues. AYAs are frequently diagnosed late, after a prolonged period of misdiagnosis. The epidemiology, biology, prognosis, and overall management of these tumors differ from those of both older and younger age groups. AYAs are usually in a transitional phase in their lives, and brain tumors in this age group carry a better prognosis than in older adults; thus, special attention should be paid to survivorship care. Fertility and other treatment-related sequelae that affect the quality of life, as well as the increased risk of secondary malignancies in long-term survivors, are such examples. Although most AYAs are managed by adult or, to a lesser extent pediatric, oncologists, a multidisciplinary approach in the setting of specialized centers with increased participation in clinical trials is preferable. End-of-life and palliative care remain an unmet need for these patients, because most physicians lack the training to discuss such issues with young patients.

Endoscopic transnasal resection of optic pathway pilocytic astrocytoma

PURPOSE

Optic pathway gliomas (OPGs) are low-grade neoplasms that primarily affect children. The management of OPGs remains controversial. Reports on the use of the endoscopic endonasal approach (EEA) in OPGs are extremely limited, and no such reports exist on its utility for pediatric OPGs. Here, we report our results and experience with OPGs treated with the EEA.

METHODS

We retrospectively reviewed the medical records of OPG patients who were treated surgically via the EEA at our institutions from 2015 to 2017. Data on the demographics, clinical presentation, surgical complications, clinical outcomes, radiological imaging, and visual outcomes were recorded for each patient.

RESULTS

Four cases were identified, with visual disturbances being the predominant complaint. The mean patient age was 15.5 years. Three cases showed normal preoperative hormonal profiles, but one patient had hypothyroidism. All tumors identified in this study were World Health Organization grade I pilocytic astrocytomas. Surgical complications included hypopituitarism in two patients, meningitis in two patients, cerebrospinal fluid leak in one patient, and transient diabetes insipidus in one patient. No patient experienced worsening neurological or visual symptoms postoperatively.

CONCLUSIONS

Although our data are preliminary, the EEA provides a direct corridor to OPG with acceptable results in terms of tumor resection and visual outcomes. Hypothalamic-pituitary axis dysfunction remains a limitation of any treatment modality for OPGs and should be considered whenever possible. Definitive conclusions are pending as the learning curve of this approach is steep. Further work is needed to understand patient selection for such an approach.

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.

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.

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.