Atypical Teratoid/Rhabdoid Tumor of the Central Nervous System in Children: Case Reports and Literature Review

Navigating the complexity of atypical teratoid/rhabdoid tumor (ATRT) in pediatric neuro-oncology: Insights from clinical spectrum to therapeutic challenges

INTRODUCTION AND IMPORTANCE

Atypical teratoid/rhabdoid tumor (ATRT) is a rare and aggressive pediatric central nervous system malignancy, accounting for only 1-2 % of cases. Primarily affecting children under three years old, ATRT poses significant diagnostic and therapeutic challenges, with high recurrence rates and poor prognosis due to its rapid progression and lack of a standardized treatment protocol.

CASE PRESENTATION

We report the case of a 2-year-old male diagnosed with infratentorial ATRT after presenting with abnormal gait, vomiting, and ataxia following minor head trauma. Magnetic resonance imaging (MRI) revealed a mixed solid-cystic cerebellar lesion, prompting surgical resection. Despite postoperative chemotherapy, tumor progression was noted, leading to a second craniotomy, which achieved complete resection. Serial follow-up MRI until February 2025 showed no evidence of recurrence, and the patient remains symptom-free four years post-treatment.

CONCLUSION

This case underscores the complexities of ATRT management, emphasizing the importance of early diagnosis, aggressive multimodal therapy, and vigilant radiological follow-up. While ATRT shares imaging similarities with medulloblastomas, its distinct histopathological features necessitate tailored treatment strategies. Maximal safe resection, followed by intensive chemotherapy, remains the cornerstone of treatment, highlighting the need for a multidisciplinary approach to improve long-term outcomes in pediatric ATRT patients.

Proteomic-based stemness score measures oncogenic dedifferentiation and enables the identification of druggable targets

Cancer progression and therapeutic resistance are closely linked to a stemness phenotype. Here, we introduce a protein-expression-based stemness index (PROTsi) to evaluate oncogenic dedifferentiation in relation to histopathology, molecular features, and clinical outcomes. Utilizing datasets from the Clinical Proteomic Tumor Analysis Consortium across 11 tumor types, we validate PROTsi's effectiveness in accurately quantifying stem-like features. Through integration of PROTsi with multi-omics, including protein post-translational modifications, we identify molecular features associated with stemness and proteins that act as active nodes within transcriptional networks, driving tumor aggressiveness. Proteins highly correlated with stemness were identified as potential drug targets, both shared and tumor specific. These stemness-associated proteins demonstrate predictive value for clinical outcomes, as confirmed by immunohistochemistry in multiple samples. The findings emphasize PROTsi's efficacy as a valuable tool for selecting predictive protein targets, a crucial step in customizing anti-cancer therapy and advancing the clinical development of cures for cancer patients.

Multifocal atypical teratoid/rhabdoid tumour in an infant-a rare case report

BACKGROUND

Atypical teratoid/rhabdoid tumours (AT/RT) are uncommon but aggressive, malignant tumours in the paediatric age group. Presentation of concomitant supratentorial and infratentorial lesions in an infant is extremely rare. We discuss an infant diagnosed with such lesions. Systematic PubMed search was conducted using keywords 'atypical teratoid /rhabdoid tumor', 'paediatric' and 'multifocal'. Reports were included for patients younger than 18 years with two or more lesions. The search yielded additional five cases and were tabulated. Age, sex, location, treatment given and survival/outcome were noted.

CASE REPORT

A 10-month-old child presented with complaints of drowsiness and intractable vomiting. Imaging showed multifocal supra- and infratentorial lesions with obstructive hydrocephalus. The child underwent ventriculoperitoneal shunt followed by surgical removal of the posterior fossa lesion. Histopathological features were consistent with AT/RT.

CONCLUSIONS

Multifocal AT/RT are very rare. The impact of multifocality in the outcome is not known as very few reports are available. Newer targeted therapies may offer insight in improving outcomes in the future.

Evaluation of INI1 Protein Expression Through IHC Study in Pediatric High-Grade Brain Tumors in South of Iran in 2008-2021

Background & Objective

Brain tumors are the most frequent solid tumors in children. High-grade tumors are more challenging in diagnosis. Atypical teratoid rhabdoid tumor (ATRT) may be mistaken for other high-grade brain tumors. Molecular genetic analysis of ATRT has shown deletion and mutation in the hSNF5/INI1 gene in most of the cases. The INI1 protein expression can be helpful for the accurate diagnosis.

Methods

In this study, immunohistochemical staining (IHC) using INI1 antibody was performed to determine the possibility of ATRT misdiagnosis. Totally, 147 tumors including 6 ATRTs, 81 medulloblastomas, and 60 other CNS tumors were examined in children between 0 and 17 years old.

Results

No nuclear staining was found in the six ATRT cases, while most of other CNS tumors demonstrated nuclear staining. Five cases were previously diagnosed with medulloblastoma, primitive neuroectodermal tumor (PNET), and anaplastic oligodendroglioma, while the diagnoses were changed to ATRT based on the re-evaluation of the H&E slides and INI1 study. Additionally, two cases were recurrent tumors whose features were consistent with those of ATRT. The INI1 immunostaining was negative in these cases.

Conclusion

INI1 was very helpful in distinguishing ATRT from its mimickers in challenging cases. All known ATRT cases in this study were immunonegative for INI1. Thus, INI1 is recommended to be used in the initial IHC panel for the high-grade brain tumors, especially in children under the age of three years, so that they can benefit from intensified therapeutic regimens.

Pediatric Posterior Fossa ATRT: A Case Report, New Treatment Strategies and Perspectives

Posterior fossa atypical teratoid rhabdoid tumor (ATRT) is a rare childhood tumor usually associated with a dismal prognosis. Although upfront surgical gross total resection (GTR) has classically been the first line of treatment, new multimodal treatments, including two-stage surgery, are showing promising results in terms of overall survival (OS) and complication rate. We present a case of a 9-month-old child treated with two-staged surgery and chemotherapy. When deemed risky, multimodal treatments, including staged surgeries, can be a safe alternative to reduce surgical mortality and morbidity. At 23 months old, the patient had normal global development and no major impact on quality of life. We, therefore, discuss the most recent advancements from a treatment perspective, including molecular targeting.

Targeted treatment of solid tumors in pediatric precision oncology

The treatment of childhood solid cancer has markedly evolved in recent years following a refined molecular characterization and the introduction of novel targeted drugs. On one hand, larger sequencing studies have revealed a spectrum of mutations in pediatric tumors different from adults. On the other hand, specific mutations or immune dysregulated pathways have been targeted in preclinical and clinical studies, with heterogeneous results. Of note, the development of national platforms for tumor molecular profiling and, in less measure, for targeted treatment, has been essential in the process. However, many of the available molecules have been tested only in relapsed or refractory patients, and have proven poorly effective, at least in monotherapy. Our future approaches should certainly aim at improving the access to molecular characterization, to obtain a deeper picture of the distinctive phenotype of childhood cancer. In parallel, the implementation of access to novel drugs should not only be limited to basket or umbrella studies but also to larger, multi-drug international studies. In this paper we reviewed the molecular features and the main available therapeutic options in pediatric solid cancer, focusing on available targeted drugs and ongoing investigations, aiming at providing a useful tool to navigate the heterogeneity of this promising but complex field.