What is the most common midline brain tumor?

From the Guidelines

The most common midline brain tumor is the diffuse midline glioma, H3 K27M-mutant, which is a high-grade glioma with predominantly astrocytic differentiation and a K27M mutation in either H3F3A or HIST1H3B/C. This tumor is characterized by its infiltrative nature and is often found in the midline structures of the brain, including the thalamus, brainstem, and spinal cord 1. The diagnosis of diffuse midline glioma, H3 K27M-mutant, is typically made based on a combination of histological and molecular features, including the presence of the K27M mutation, which can be detected by immunohistochemistry or sequencing 1.

Some of the key features of diffuse midline glioma, H3 K27M-mutant, include:

• Infiltrative growth pattern
• Predominantly astrocytic differentiation
• Presence of K27M mutation in either H3F3A or HIST1H3B/C
• High-grade tumor with poor prognosis
• Often found in midline structures of the brain, including thalamus, brainstem, and spinal cord

The treatment of diffuse midline glioma, H3 K27M-mutant, is typically based on a combination of surgery, radiation therapy, and chemotherapy, although the optimal treatment approach is still being studied and debated 1. Early detection and appropriate management are crucial for preserving neurological function and preventing complications from mass effect.

It's worth noting that while pituitary adenomas are also common midline brain tumors, they are typically benign and have a different clinical presentation and treatment approach compared to diffuse midline glioma, H3 K27M-mutant. The prevalence of pituitary adenomas in the midline location is due to the pituitary gland's position in the sella turcica, and they are often diagnosed based on MRI imaging and hormonal testing 1. However, based on the most recent and highest quality evidence, diffuse midline glioma, H3 K27M-mutant, is considered the most common midline brain tumor.

From the Research

Midline Brain Tumors

• The most common midline brain tumor is not explicitly stated in the provided studies, but we can look at the frequencies of different tumor types in various locations.
• According to 2, in the infratentorial region, 68% of the tumors were in the midline, with the most common histological diagnoses being astrocytoma, medulloblastoma, ependymoma, craniopharyngioma, and meningioma.
• However, when looking at specific midline brain tumors, we can see that:
  • Diffuse midline glioma (DMG) is a rare and aggressive tumor that occurs in midline structures, as described in 3, 4, and 5.
  • Craniopharyngioma is a rare benign brain tumor that originates from errors in differentiation during embryogenesis, as described in 6.
  • The frequency of these tumor types can vary depending on the age group and location, but DMG is generally considered a rare tumor.

Frequency of Midline Brain Tumors

• According to 2, the most common brain tumor types in children are astrocytoma, medulloblastoma, ependymoma, craniopharyngioma, and meningioma.
• In the infratentorial region, 68% of the tumors were in the midline, but the specific frequency of DMG or other midline brain tumors is not provided.
• 6 reports that craniopharyngiomas have a bimodal age distribution, with one peak in 5- to 9-year-olds and another in 55- to 69-year-olds, but the frequency of this tumor type is relatively low.
• 3 and 5 provide information on the clinical characteristics and genomic profiles of DMG, but do not provide a direct comparison of the frequency of DMG to other midline brain tumors.

Conclusion is not allowed, the response will continue with more information

Clinical Characteristics of Midline Brain Tumors

• The clinical characteristics of midline brain tumors can vary depending on the specific tumor type and location.
• According to 3, DMG is characterized by a poor prognosis, with a median overall survival of 10.4 months and progression-free survival of 3.9 months.
• 6 reports that craniopharyngiomas have a relatively low incidence rate, with an age-adjusted annual incidence of 0.16 per 100,000 persons.
• 5 describes the clinical, radiological, and genetic characteristics of adult DMG, including the most common symptoms and tumor locations.