Types Of Brain Tumors In Adults

Common Primary Brain Tumors in Adults

Gliomas: The Most Prevalent Malignant Brain Tumors

Gliomas are the most common type of malignant primary brain tumors in adults. They originate from glial cells and are classified into several subtypes based on their histological and molecular characteristics. The World Health Organization (WHO) 2021 classification has refined the categorization of gliomas into three main types: astrocytoma, isocitrate dehydrogenase (IDH) mutant; oligodendroglioma, IDH mutant and 1p/19q codeleted; and glioblastoma, IDH wild type . Glioblastoma, in particular, is known for its aggressive nature and poor prognosis.

Primary CNS Lymphomas: Increasing Incidence

Primary central nervous system (CNS) lymphomas are another significant type of brain tumor in adults. These tumors have seen a notable increase in incidence over the past two decades. They are particularly challenging to treat, especially in elderly patients, due to the potential neurotoxic effects of combined methotrexate-based chemotherapy and radiotherapy.

Brainstem Gliomas: Rare but Notable

Brainstem gliomas, although rare, represent a heterogeneous group of tumors with varying pathology and prognosis. Diffuse intrinsic pontine gliomas are the most common subtype in adults and, while aggressive, they tend to have a more favorable prognosis compared to their pediatric counterparts.

Advances in Molecular Classification and Treatment

Molecular Genetic Analysis in Gliomas

Recent advances in molecular biology have significantly improved the understanding and classification of gliomas. Key genetic alterations such as IDH mutations, 1p/19q codeletion, H3 Lys27Met, and RELA-fusion are now integral to the diagnosis and treatment planning of these tumors. These molecular markers are combined with histological analysis in the WHO 2016 and 2021 classifications, enhancing the accuracy of diagnosis and guiding therapeutic decisions .

Targeted Therapies and Immunotherapies

The integration of molecular profiling into the classification of brain tumors has paved the way for the development of targeted therapies and immunotherapies. Although single-agent therapies have shown limited success, combination therapies are being explored to achieve more effective and durable responses. Ongoing research is focused on molecular targeted therapies, immunotherapies, gene therapies, and novel drug-delivery technologies .

Other Notable Brain Tumors in Adults

Meningiomas

Meningiomas are another common type of brain tumor in adults. These tumors arise from the meninges, the protective layers surrounding the brain and spinal cord. They are typically benign but can cause significant symptoms due to their location and size.

Ependymomas and Medulloblastomas

Ependymomas and medulloblastomas, while more common in children, can also occur in adults. Advances in the classification of these tumors have enabled better identification of low-risk cases, which may benefit from less aggressive treatment strategies.

Conclusion

The landscape of brain tumor classification and treatment in adults has evolved significantly with advances in molecular biology and genetic profiling. Gliomas remain the most common and challenging type of malignant brain tumor, but the integration of molecular markers into their classification has improved diagnostic accuracy and treatment planning. Primary CNS lymphomas and brainstem gliomas are also notable for their unique challenges and treatment considerations. Continued research and development of targeted therapies hold promise for improving outcomes for patients with these complex and diverse tumors.

Types of brain tumors in adults

Summary

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