Infant brain tumors: a neuropathologic population-based institutional reappraisal

Non-coding RNAs as Key Regulators of the Notch Signaling Pathway in Glioblastoma: Diagnostic, Prognostic, and Therapeutic Targets

Glioblastoma multiforme (GBM) is a highly invasive brain malignancy originating from astrocytes, accounting for approximately 30% of central nervous system malignancies. Despite advancements in therapeutic strategies including surgery, chemotherapy, and radiopharmaceutical drugs, the prognosis for GBM patients remains dismal. The aggressive nature of GBM necessitates the identification of molecular targets and the exploration of effective treatments to inhibit its proliferation. The Notch signaling pathway, which plays a critical role in cellular homeostasis, becomes deregulated in GBM, leading to increased expression of pathway target genes such as MYC, Hes1, and Hey1, thereby promoting cellular proliferation and differentiation. Recent research has highlighted the regulatory role of non-coding RNAs (ncRNAs) in modulating Notch signaling by targeting critical mRNA expression at the post-transcriptional or transcriptional levels. Specifically, various types of ncRNAs, including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), have been shown to control multiple target genes and significantly contribute to the carcinogenesis of GBM. Furthermore, these ncRNAs hold promise as prognostic and predictive markers for GBM. This review aims to summarize the latest studies investigating the regulatory effects of ncRNAs on the Notch signaling pathway in GBM.

Changes to pediatric brain tumors in 2021 World Health Organization classification of tumors of the central nervous system

New tumor types are continuously being described with advances in molecular testing and genomic analysis resulting in better prognostics, new targeted therapy options and improved patient outcomes. As a result of these advances, pathological classification of tumors is periodically updated with new editions of the World Health Organization (WHO) Classification of Tumors books. In 2021, WHO Classification of Tumors of the Central Nervous System, 5^th edition (CNS5), was published with major changes in pediatric brain tumors officially recognized including pediatric gliomas being separated from adult gliomas, ependymomas being categorized based on anatomical compartment and many new tumor types, most of them seen in children. Additional general changes, such as tumor grading now being done within tumor types rather than across entities and changes in definition of glioblastoma, are also relevant to pediatric neuro-oncology practice. The purpose of this manuscript is to highlight the major changes in pediatric brain tumors in CNS5 most relevant to radiologists. Additionally, brief descriptions of newly recognized entities will be presented with a focus on imaging findings.

Infantile Brain Tumors: A Review of Literature and Future Perspectives

Brain tumors in infants including those diagnosed in fetal age, newborns and under a year old represent less than 10% of pediatric nervous system tumors and present differently when compared with older children in terms of clinical traits, location and histology. The most frequent clinical finding is a macrocephaly but non-specific symptoms can also be associated. The prognosis is usually poor and depends on several factors. Surgery continues to be the main option in terms of therapeutic strategies whereas the role of chemotherapy is not yet well defined and radiotherapy is exceptionally undertaken. In view of this situation, a molecular characterization could assist in providing therapeutic options for these tumors. This review highlights the recent advances in the diagnosis and treatment of brain tumors in infants with a particular focus on the molecular landscape and future clinical applications.

Infantile/Congenital High-Grade Gliomas: Molecular Features and Therapeutic Perspectives

Brain tumors in infants account for less than 10% of all pediatric nervous system tumors. They include tumors diagnosed in fetal age, neonatal age and in the first years of life. Among these, high-grade gliomas (HGGs) are a specific entity with a paradoxical clinical course that sets them apart from their pediatric and adult counterparts. Currently, surgery represents the main therapeutic strategy in the management of these tumors. Chemotherapy does not have a well-defined role whilst radiotherapy is rarely performed, considering its late effects. Information about molecular characterization is still limited, but it could represent a new fundamental tool in the therapeutic perspective of these tumors. Chimeric proteins derived from the fusion of several genes with neurotrophic tyrosine receptor kinase mutations have been described in high-grade gliomas in infants as well as in neonatal age and the recent discovery of targeted drugs may change the long-term prognosis of these tumors, along with other target-driven therapies. The aim of this mini review is to highlight the recent advances in the diagnosis and treatment of high-grade gliomas in infants with a particular focus on the molecular landscape of these neoplasms and future clinical applications.

Uncommon pediatric tumors of the posterior fossa: pathologic and molecular features

INTRODUCTION

Three tumors are commonly encountered in the posterior fossa of children: pilocytic astrocytoma (PA), medulloblastoma (MB), and ependymoma. However, a variety of additional tumors may occasionally be appreciated. Appropriate and successful treatment of these less common cases is predicated upon correct pathologic diagnosis.

METHODS/RESULTS

Reviewed herein are five less common tumors that may affect the posterior fossa of children: (1) "embryonal tumor with multilayered rosettes" (ETMR); (2) "cribriform neuroepithelial tumor" (CRINET); (3) "rosette-forming glioneuronal tumor" (RGNT); (4) "diffuse pilocytic astrocytoma" (dPA); and, (5) "desmoplastic small round cell tumor" (DSRCT). Each of the foregoing has a varying predilection for children and a posterior fossa location. For example, RGNT by definition arises in association with the 4th ventricle; while the mean age of those afflicted is 33, children may also be affected. Likewise, descriptions of dPA are generally restricted to the posterior fossa, and in particular, the cerebellum of children. Alternatively, DSRCT is a form of undifferentiated sarcoma that characteristically originates in the abdomen of children, but on occasion arises from the tentorium of young adults and children. The relevant molecular genetic underpinnings for each of the tumors highlighted herein have been well described and may carry diagnostic utility, not to mention clues as to underlying etiology.

CONCLUSION

A number of pediatric brain tumors have a tendency to occur in the posterior fossa. While far less common than PA, MB, or ependymoma, the entities highlighted herein appear to have a degree of proclivity for the posterior fossa of children and as such warrant due consideration in the clinicopathologic workup of these cases.

Radiological features of infantile glioblastoma and desmoplastic infantile tumors: British Columbia's Children's Hospital experience

OBJECT Two of the more common infantile brain tumors, glioblastoma multiforme (GBM) and desmoplastic infantile tumors (DITs), can be difficult to distinguish on MRI. Both tumors occur in the supratentorial compartment and both have solid and cystic components. Differentiating between the 2 on MRI studies could assist the surgeon in discussions with family and child management. The authors report on their institutional experience with both tumors, focusing on radio-graphic features, especially the diffusion studies, which might be useful in distinguishing between infantile GBM and DIT. METHODS A retrospective review was undertaken of all infantile brain tumors treated at British Columbia's Children's Hospital between 1982 and 2012, and cases of GBM and DIT were recorded. Only cases that had imaging were included in the study. A literature review was completed to identify reported cases of infantile GBM and DIT. Only reports that described or included radiological studies (particularly MRI) of the tumors were included. Certain radiographic features of the tumors were reviewed, including location, size, consistency, pattern of enhancement, and features on MR diffusion studies. RESULTS Of 70 cases of infantile brain tumors, 2 GBM cases and 3 DIT cases (all 3 of which were desmoplastic infantile gangliogliomas [DIGs]) met the inclusion criteria. The radiological studies obtained in all 5 cases were reviewed by a neuroradiologist. All 5 patients had supratentorial tumors with cystic-solid consistency. Diffusion MRI studies showed restricted diffusion in the 2 GBM cases, but no evidence of restricted diffusion in the DIG tumors. The GBM tumors were heterogeneously enhancing, and the DIG tumors showed avid and homogeneous enhancement. The literature review revealed 29 cases of infantile GBM and 32 cases of DIG/DIT that met the inclusion criteria. The tumors were large in both groups. The tumors were cystic-solid in consistency in 10 of 30 (33%) of GBM cases and 28 of 32 (87.5%) of DIT cases. The contrast enhancement was heterogeneous in 9 of 30 (30%) GBM cases, and it was homogeneous and avid in 27 of 32 (84%) of DIT cases. Diffusion studies were recorded in 2 published infantile GBM cases, and in both of them diffusion was restricted. The authors only found 1 report that discussed DIG tumor features on MR diffusion studies, but the interpretation was difficult and unclear. CONCLUSIONS Magnetic resonance imaging, especially diffusion-weighted imaging, may be a useful aid in distinguishing between infantile GBM and DIT tumors, with infantile GBM demonstrating restricted diffusion.

Epidemiology of brain tumors in children aged two and under: A 10-year single-institute study

The aim of present study was to evaluate the incidence, clinical symptoms, pathological characteristics, surgical treatment strategies and prognosis of brain tumors in children aged two and under. The current study obtained data regarding 32 consecutive infants and young children aged two years and under, who were treated for brain tumors in the Children’s Hospital of Fudan University (Shanghai, China) between 2003 and 2013. The types of tumor, clinical manifestations, location, histological features, applied treatment strategies and outcomes were retrospectively evaluated. The male to female ratio was 1.13:1, and among a total of 32 tumors, 14 (43.8%) were suptratentorial and 18 (56.3%) were infratentorial. Intracranial hypertension was the most common onset symptom, and astrocytoma was the most common tumor type (10 cases; 31.3%), followed by ependymoma (nine cases; 28.1%) and medulloblastoma (six cases; 18.8%). Surgical tumor resection was performed in 20 patients (62.5%), who experienced a mean post-operative survival time of 67.6 months. By contrast, conservative treatment with medications was administered in 12 patients (37.5%), with a mean survival time of 25.3 months. Furthermore, four patients underwent conservative therapy combined with ventriculoperitoneal shunting to relieve intracranial pressure arising from cerebrospinal fluid accumulation, resulting in a mean survival time of 10.5 months. In conclusion, the present study indicates that surgical tumor resection may improve the overall prognosis of infants and young children aged two years and under who presented with brain tumors. In addition, ventriculoperitoneal shunts may facilitate pre- and post-operative improvement in clinical symptoms by relieving intracranial pressure; however, the shunts do not appear to increase long-term survival. Furthermore, high surgical risk is an important prognostic factor in this pediatric patient population.

Central nervous system tumors in the first year of life: a clinical and pathologic experience from a single cancer center

PURPOSE

This study aims to review our experience with central nervous system (CNS) tumors occurring during the first year of life and to report differing features found in our series.

METHODS

This is a retrospective study of infants with CNS tumors diagnosed at our institution from 2006 to 2011.

RESULTS

A total of 19 cases were identified, with a median age of 232 days and predominance of male gender. Males were younger than females at the time of diagnosis (p value = 0.039). There were 13 low-grade tumors, glial tumors being the most common (11/13, p value = 0.003) and six high-grade tumors, atypical teratoid rhabdoid tumor being the most common (4/6). Low-grade tumors predominated in the supratentorial region, while high-grade tumors were seen in the infratentorial area (p value = 0.035). Males had a predilection to have more supratentorial tumors (p value = 0.058). Four patients underwent gross total resection, and eight received chemotherapy; none received radiotherapy. Two patients had spinal cord tumors; both were of pilomyxoid astrocytoma histology. Rare tumors included hemangiopericytoma (n = 1) and atypical choroid plexus tumor (n = 1), both occurring in the supratentorial area and affecting the youngest patients in this group; they were diagnosed prenatally and at 107 days, respectively. The median progression-free and overall survivals were 269 and 667 days, respectively. Among all tested parameters, only the grade of the tumor affected the outcome.

CONCLUSIONS

Diagnosis and management of infant's CNS tumors remain challenging. Pathologists should be aware of the diversity of histological types. Assigning appropriate tumor grade is fundamental in predicting the outcome.