Related Experiment Video
Updated: Jun 16, 2025
Primary Orthotopic Glioma Xenografts Recapitulate Infiltrative Growth and Isocitrate Dehydrogenase I Mutation
Published on: January 14, 2014
Primary mismatch repair-deficient IDH-mutant astrocytoma in child: Unusual entity
Hafsa El Ouazzani1, Nadia Cherradi1
1Department of Pathology HSR, Ibn Sina University Hospital Center, Morocco; Mohammed V University in Rabat, Morocco.
Introduction:
"Primary Mismatch Repair-Deficient IDH-mutant Astrocytoma" (PMMRDIA) is a newly identified high-grade glioma with a poor prognosis. It has not been officially recognized as a distinct entity in the 5th edition of the WHO Classification of Central Nervous System Tumors 2021, making its diagnosis challenging.
Case Presentation:
To highlight this entity, we present the case of a 7-year-old boy with a family history of cerebral tumor among the father's relatives and first-degree parental consanguinity. He experienced increased intracranial hypertension and inguinal café-au-lait macules. Brain imaging revealed a cystic and solid mass with irregular enhancement in the left parietal lobe, indicating a possible Pilocytic astrocytoma. The final diagnosis of PMMRDIA was confirmed through histological, immunohistochemical, and molecular analysis.
Clinical Discussion:
This tumor is mainly observed in children and is characterized by microsatellite instability (MSI) and high tumor mutational burden (TMB). MSI is known to occur in recurrent IDH-mutant gliomas as a resistance mechanism towards alkylating chemotherapy.
Conclusion:
In PMMRDIA, MSI can be a good predictive biomarker for responding to immunotherapy, which could improve the outcome of these children.
Insights
Primary Mismatch Repair-Deficient IDH-mutant Astrocytoma (PMMRDIA) is a rare pediatric glioma. Microsatellite instability (MSI) in PMMRDIA may predict response to immunotherapy, potentially improving outcomes.
Area of Science:
- Neuro-oncology
- Pediatric oncology
- Molecular diagnostics
Background:
- Primary Mismatch Repair-Deficient IDH-mutant Astrocytoma (PMMRDIA) is a high-grade glioma with a poor prognosis.
- This entity is not yet officially recognized in the WHO CNS Tumor Classification 2021, complicating diagnosis.
Related Concept Videos
01:20Mismatch Repair
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
01:20The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...