Diffuse midline glioma

Diffuse midline glioma (DMG) is a type of brain tumor that primarily affects children and young adults. It is characterized by its location in the midline structures of the brain and spinal cord, and its diffuse growth pattern. DMG is a highly aggressive tumor, with a poor prognosis.

Epidemiology

DMG accounts for approximately 10-20% of all pediatric brain tumors. It is most commonly diagnosed in children between the ages of 5 and 9, but can occur at any age. The incidence of DMG is slightly higher in males than in females.

Pathophysiology

DMG originates from the glial cells, which are cells in the brain and spinal cord that support and protect the neurons. The tumor grows diffusely, infiltrating the surrounding normal brain tissue, which makes it difficult to completely remove with surgery. The most common location for DMG is in the pons, a part of the brainstem, but it can also occur in other midline structures such as the thalamus and spinal cord.

Clinical Presentation

The symptoms of DMG depend on the location of the tumor. Common symptoms include headache, nausea and vomiting, difficulty walking, weakness on one side of the body, and problems with speech and swallowing. In some cases, the tumor can cause hydrocephalus, a condition in which excess cerebrospinal fluid builds up in the brain, leading to increased pressure and swelling.

Diagnosis

The diagnosis of DMG is usually made based on imaging studies, such as magnetic resonance imaging (MRI). The tumor typically appears as a diffuse, hyperintense lesion on T2-weighted images. In some cases, a biopsy may be performed to confirm the diagnosis and determine the molecular characteristics of the tumor.

Treatment

The standard treatment for DMG is radiation therapy, which can help to slow the growth of the tumor and relieve symptoms. However, due to the diffuse nature of the tumor and its location in critical areas of the brain, it is usually not possible to completely remove the tumor with surgery. Chemotherapy may also be used, but its effectiveness is limited. Recent advances in molecular biology have led to the development of targeted therapies, which aim to specifically attack the genetic mutations that drive the growth of the tumor.

Prognosis

The prognosis for DMG is generally poor, with a median survival of less than one year. However, survival can vary depending on the age of the patient, the location of the tumor, and the specific genetic mutations present in the tumor.