概述
Diffuse midline glioma (DMG) is a rare type of cancerous brain tumor. It's most common in children between the ages of 5 and 10 years old, though it can also affect adults. The name means:
- Diffuse: The cancer cells have spread beyond the tumor and into healthy brain tissue.
- Midline: The tumor is found in the middle section of the central nervous system, usually the thalamus, spinal cord or brainstem, also called the pons.
- Glioma: The tumor grew from glial cells, which are "helper" cells in the white matter of the brain.
The term "diffuse intrinsic pontine glioma" (DIPG) used to be used for tumors in the pons area of the brain. Now the term DMG is used to describe these tumors instead of the older term, DIPG. DIPG also may be called H3K27-altered DMG.
The name DIPG means:
- Diffuse: The cancer cells have spread beyond the tumor into healthy brain tissue.
- Intrinsic: The tumor grew from inside the brain tissue.
- Pontine: The tumor is found in the pons, the area of the brainstem that helps control things such as breathing and heartbeats.
- Glioma: The tumor grew from glial cells, which are helper cells found in the white matter of the brain.
DMG is an aggressive type of cancer. Symptoms of DMG usually start suddenly and quickly get worse. DMG may be diagnosed with a review of symptoms, a brain MRI and other tests. There is no cure for DMG. The most common treatments are radiation therapy and chemotherapy. These treatments aim to ease discomfort and help extend life, but they do not cure the cancer.
症状
Symptoms of diffuse pontine glioma (DMG) depend on where in the central nervous system the tumor is growing. Symptoms at first may be mild and easy to overlook. But they get worse over a few weeks or months. It's very difficult to diagnose DMG in the early stages.
Common symptoms of DMG include:
- Drooping on one side of the face.
- Weakness in the facial muscles.
- Weakness in the arms and legs, particularly on one side.
- Clumsiness.
- Fatigue.
- Headaches, particularly in the morning.
- Nausea and vomiting.
- Problems with speech or swallowing.
- Balance problems.
- Difficulty walking.
- Tingling or numbness, which may affect the face, arms, hands or legs.
- Difficulty concentrating.
- Seizures.
- Back pain.
- Changes in bladder and bowel function.
- Vision problems, including blurry or double vision.
- Hearing problems, including loss of hearing.
- Behavior changes, such as irritability or trouble at school.
- Gaining weight.
When to seek care
Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.
病因
The cause of diffuse midline glioma (DMG) isn't completely understood. It's thought to be caused by a gene change that is not expected, such as a random mistake. Genes provide a set of instructions for every cell that tell it how to grow and function. Gene changes, also called mutations, happen when there is an error in these instructions.
The mutations that cause DMG affect the H3K27-altered gene, which is a histone gene. Histone genes help package DNA in cells and manage which genes are turned off or on. When histone genes change, cells cannot regulate themselves properly and don't stop growing when they should. This allows the cells to multiply very quickly and form a tumor.
Another cause of DMG is a change, also called disruption, in the healthy growth of glial cells. Glial cells are part of the white matter of the brain. They support healthy cell development and function. Also caused by the histone gene mutation, this disruption causes the glial cells to grow out of control.
It's possible that DMG may be related to the rapid brain growth of children between the ages of 5 and 10, since this is the most common age for people to be diagnosed with DMG. This time period where the brain grows rapidly may make the brain at risk for these changes in genes.
风险因素
There are no known risk factors for diffuse midline glioma and no known way to prevent these tumors.