Decoding Brain Tumors: How MRI Can Spot Subtypes of ATRT
"New research reveals that MRI scans can help identify molecular subgroups of atypical teratoid/rhabdoid tumors (ATRT), leading to better diagnoses and targeted treatments."
Atypical teratoid/rhabdoid tumors (ATRT) are rare and aggressive brain tumors that primarily affect young children. Making up only 1-2% of all pediatric brain tumors, they can account for up to 20% of brain tumor cases in children under three years old. These tumors are known for their rapid growth and resistance to conventional treatments, making early and accurate diagnosis critical.
Recent advances in molecular biology have identified three distinct subgroups of ATRT: SHH, TYR, and MYC. Each subgroup has unique genetic and epigenetic characteristics, leading to variations in their behavior and response to therapy. Understanding these molecular differences is crucial for developing targeted treatments that can improve patient outcomes.
Magnetic resonance imaging (MRI) is a powerful tool for visualizing brain tumors and assessing their characteristics. While MRI can detect ATRT, distinguishing between the molecular subgroups has been challenging. However, a new study reveals that specific MRI features can serve as surrogates for these subgroups, providing valuable information for diagnosis and treatment planning.
A Rare, Serious Childhood Tumor
Atypical teratoid/rhabdoid tumor (ATRT) is a rare malignant brain tumor that affects children age 3 and younger and is associated with significant mortality. It is diagnosed using specific molecular and methylation features, according to a 2025 epidemiology analysis. For context, the National Cancer Institute reports that about 0.6% of people will be diagnosed with brain and other nervous system cancer during their lifetime, and an estimated 196,343 people in the United States were living with those cancers in 2023; these figures cover brain and other nervous system cancers broadly, not ATRT alone.
Multimodal Care and Treatment Challenges
ATRT treatment can involve intensive multimodal therapy, and the Vienna experience described improved long-term survival with intensive multimodal treatment and delayed radiotherapy during 1992–2012. An IRS-III long-term follow-up report recommends that regimen as standard care for localized ATRT, citing favorable survival and the possibility of giving radiotherapy after induction without compromising outcomes. The report also highlights radiotherapy’s importance for localized disease and suggests delayed treatment may reduce treatment-related toxicity. Even with recent clinical-trial results indicating ATRT can be curable, outcomes remain poor compared with other CNS embryonal tumors.
From Recognition to Molecular Insights
A 2025 historical review describes ATRT as a rare, highly aggressive embryonal CNS tumor of infancy and childhood that has been recognized as a distinct entity since the late 20th century. It says breakthroughs in molecular pathology and neuroimaging have transformed diagnostic, prognostic, and therapeutic approaches. A separate 2025 review describes ATRT as predominantly affecting infants and young children and notes that it can arise throughout the CNS, while malignant rhabdoid tumors also occur outside the brain.
MRI: A Window into ATRT Subtypes
Researchers analyzed MRI scans from 43 patients with known ATRT molecular subgroup status. They looked for patterns in tumor location, peritumoral edema (swelling around the tumor), the presence of cysts, contrast enhancement, and other imaging features. The goal was to identify MRI characteristics that correlated with each of the three ATRT subgroups.
- ATRT-TYR: Primarily located in the infratentorial region (lower part of the brain)
- ATRT-MYC: Often showed more peritumoral edema (swelling) compared to other subgroups.
- ATRT-SHH: More frequently exhibited peripheral tumor cysts (fluid-filled sacs around the tumor). Contrast enhancement (how the tumor appears after injecting a contrast dye) was less common in this subgroup.
Subtypes and Molecular Diagnosis
A case series on ATRT of the lateral ventricle reports that the TYR subgroup has the most favorable prognosis, while the MYC subgroup has the poorest clinical outcomes. A review of pediatric supratentorial tumors says that supratentorial location is common in ATRT and is most frequent in the ATRT-MYC subtype, reporting figures of 50% and 70% from two cited studies. Another review traces AT/RT’s recognition to cytogenetic identification of monosomy 22 in renal rhabdoid tumors and describes CNS tumors characterized by SMARCB1 (INI-1) or SMARCA4 (BRG-1) alterations in the SWI/SNF chromatin-remodeling complex.
Aggressive Disease in Young Children
ATRT is described by Mayo Clinic as a rare, fast-growing brain or spinal tumor in children. MD Anderson likewise characterizes it as a fast-growing cancerous CNS tumor that mostly affects young children. The National Brain Tumor Society identifies AT/RT as a high-grade, fast-growing embryonal tumor that primarily affects very young children, though it can also occur in older children and young adults.
Treatment Must Balance Control and Toxicity
A 2025 review describes ATRT as a rare, aggressive CNS tumor whose early age of onset and the developing brain’s vulnerability to treatment-related toxicity create a therapeutic dilemma. It reports that recent protocols have relied on multimodal approaches, with modest increments in survival. A 2020 review says that combining highly conformal proton beam therapy with molecular subgrouping may help guide treatment strategies for embryonal tumors and ependymomas, but recommends evaluating these approaches in prospective clinical trials with rigorous comparison groups.
The Future of ATRT Diagnosis and Treatment
This study provides a foundation for using MRI as a surrogate marker for ATRT molecular subgroups. By identifying specific MRI features associated with each subgroup, doctors can gain valuable insights into the tumor's behavior and potential response to therapy.
ATRT Can Also Occur in Adults
A 2017 report presented a quantitative analysis of ATRT in adults, including two patients treated at the authors’ institutions. The cases were notable because one occurred during pregnancy and one patient was a long-term survivor. These cases illustrate that, although ATRT is associated with early childhood, adult cases have also been reported.
Potential Targets and Market Projections
A June 2025 report says new research identified potential treatment targets for ATRT, a rare and aggressive pediatric brain cancer. Separately, a February 2026 market report describes the ATRT treatment market as exceeding $500 million and projects 10% CAGR growth, while outlining market segments by treatment type and region. Those market figures are projections reported by the market analysis, rather than clinical evidence of treatment effectiveness.
A Diagnosis at Nine Months
Texas Children’s shared the story of Kennedy, diagnosed with ATRT at 9 months old. Her parents, Christina and Nate, had welcomed their second child before learning that she had this rare, aggressive brain cancer, which primarily affects very young children. The account offers a personal example of the illness’s impact on a family.
The ability to differentiate ATRT subgroups based on MRI could lead to more personalized treatment strategies. For example, patients with ATRT-MYC tumors, which tend to have more edema, might benefit from therapies that target edema formation. Similarly, patients with ATRT-SHH tumors, which are less likely to show contrast enhancement, might require different imaging techniques to monitor treatment response.
While these findings are promising, further research is needed to validate the use of MRI as a surrogate marker for ATRT subgroups. Future prospective trials should incorporate MRI analysis to assess its accuracy and impact on treatment outcomes. Ultimately, this research could lead to improved diagnosis, treatment, and survival for children with ATRT.