mixed glioma

What is a Mixed Glioma?

A mixed glioma, also known as an oligoastrocytoma, is a rare type of brain tumor that contains more than one type of glial cell, including astrocytes and oligodendrocytes. This type of tumor makes up about 1% of all brain tumors and 5-10% of gliomas.

Characteristics of Mixed Gliomas

Mixed gliomas are typically slow-growing tumors that can cause symptoms such as headache, nausea, vision problems, and changes in behavior and personality. They may also be asymptomatic, especially in the early stages. The tumor's growth rate is used to grade its severity, with grades 1 and 2 being slower-growing and grades 3 and 4 being more aggressive.

Types of Gliomas

Gliomas are a type of brain tumor that originates from glial cells. There are several types of gliomas, including:

• Astrocytomas
• Ependymomas
• Oligodendrogliomas
• Mixed gliomas (also known as oligoastrocytomas)

Symptoms and Diagnosis

The initial symptoms of a mixed glioma may include headache and nausea due to increased pressure inside the brain. Vision problems, changes in behavior and personality, and optic glioma are also common symptoms. A diagnosis is typically made through imaging tests such as MRI or CT scans.

References:

• [1] Mixed gliomas contain more than one type of glial cell, including astrocytes and oligodendrocytes.
• [2] Mixed gliomas make up about 1% of all brain tumors and 5-10% of gliomas.
• [3] Symptoms may include headache, nausea, vision problems, changes in behavior and personality.
• [4] The tumor's growth rate is used to grade its severity, with grades 1 and 2 being slower-growing and grades 3 and 4 being more aggressive.
• [5] Gliomas are a type of brain tumor that originates from glial cells.
• [6] Mixed gliomas are typically slow-growing tumors.
• [7] The initial symptoms may include headache and nausea due to increased pressure inside the brain.

Diagnostic Tests for Mixed Glioma

Mixed gliomas, also known as oligoastrocytomas, are a type of brain tumor that has two types of tumor cells in it: oligodendrocytes and astrocytes. Diagnosing a mixed glioma requires a combination of physical examination, neurological examination, imaging tests, and sometimes a biopsy.

Imaging Tests

• Magnetic Resonance Imaging (MRI): MRI is the key component in the diagnosis of most brain tumors, including mixed gliomas. It uses magnets, radio waves, and a computer to produce pictures of soft tissues like tumors [2]. MRI is particularly helpful for brain imaging as it can demonstrate anatomy of the brain and details of the lesion [6].
• Computed Tomography (CT or CAT scan): CT scans use computers to create detailed images of the brain. While most glial tumors can be diagnosed on computed tomography, it is a less comprehensive imaging modality when compared to MRI [14].

Other Diagnostic Tests

• Neurological Examination: A neurological examination involves checking your vision, hearing, balance, coordination, strength, and reflexes. If there's difficulty with a certain task, it might be a clue that there could be a brain tumor [1].
• Biopsy: A surgical biopsy may be performed to help confirm the diagnosis. In this procedure, a neurosurgeon extracts a small sample of abnormal cells to test in a pathology laboratory [15].

Grading Mixed Glioma

As part of the diagnostic process, physicians will grade a mixed glioma on a scale from 1 to 4, with grades 1 and 2 describing slow-growing tumors and grades 3 and 4 describing more aggressive tumors that grow faster and are more likely to spread [3].

References:

[1] Context result 1 [2] Context result 2 [3] Context result 3 [14] Context result 14 [15] Context result 15

Treatment Options for Mixed Gliomas

Mixed gliomas, also known as oligodendrogliomas or oligoastrocytomas, are a type of brain tumor that can be challenging to treat. The treatment options for mixed gliomas may vary depending on the individual case, but they often involve a combination of surgery, chemotherapy, and radiation therapy.

• Surgery: Surgical resection is usually the first line of treatment for mixed gliomas. The goal of surgery is to remove as much of the tumor as possible while preserving surrounding brain tissue.
• Chemotherapy: Chemotherapy may be used in conjunction with surgery or as a standalone treatment option. Chemotherapy involves using medications to kill cancer cells, and it can be administered orally or intravenously.
• Radiation Therapy: Radiation therapy is another common treatment option for mixed gliomas. It involves using high-energy rays to kill cancer cells.

Targeted Therapies

In addition to traditional treatments like surgery, chemotherapy, and radiation therapy, targeted therapies are also being explored as potential treatment options for mixed gliomas. Targeted therapies involve using medications that specifically target the genetic mutations or abnormalities present in cancer cells.

• Temozolomide: Temozolomide is a medication that has been approved by the FDA for the treatment of certain types of brain tumors, including glioblastoma and anaplastic astrocytoma. It works by killing cancer cells through a process called apoptosis.
• Vorasidenib: Vorasidenib is another targeted therapy drug that has been approved by the FDA for the treatment of low-grade diffuse gliomas with a specific genetic mutation.

Clinical Trials

Clinical trials are also an important part of the treatment landscape for mixed gliomas. These trials involve testing new and innovative treatments, such as targeted therapies or immunotherapies, to see if they can improve outcomes for patients with this type of brain tumor.

• Zotiraciclib: Zotiraciclib is a medication that is currently being investigated in clinical trials as a potential treatment option for mixed gliomas. It works by inhibiting the activity of certain enzymes that are involved in cancer cell growth and proliferation.

Multidisciplinary Approach

The treatment of mixed gliomas requires a multidisciplinary approach, involving a team of healthcare professionals from various specialties, including neurosurgery, medical oncology, radiation oncology, and neuropathology. This team works together to develop an individualized treatment plan that takes into account the unique needs and circumstances of each patient.

References

• [1] Moffitt Cancer Center: Treatment for mixed gliomas may consist of surgery, chemotherapy, radiation therapy, biological therapies, immunotherapies or a combination of two or more treatments.
• [3] Yang K. (2022): Diffuse gliomas and other high-grade gliomas according to their molecule subtype are slightly intractable, with necessity of chemotherapy.
• [8] Yonk MG. (2024): Temozolomide is a medication that has been approved by the FDA for the treatment of certain types of brain tumors, including glioblastoma and anaplastic astrocytoma.
• [13] Memorial Sloan Kettering Cancer Center: Clinical trials at MSK led to the first targeted therapy drug for glioma. The U.S. Food and Drug Administration approved the drug, vorasidenib, in 2024.

Mixed Glioma Differential Diagnosis

Mixed gliomas, also known as oligoastrocytomas, are a subset of brain tumors that exhibit characteristics of both astrocytoma and oligodendroglioma. The differential diagnosis for mixed glioma involves considering various other conditions that may present with similar imaging features and clinical presentation.

Possible Differential Diagnoses:

• Oligodendroglioma: A type of brain tumor that is typically low-grade and slow-growing, often presenting with calcifications and a characteristic "fried egg" appearance on imaging studies.
• Astrocytoma: A type of brain tumor that arises from astrocytes, which are a type of glial cell. Astrocytomas can range from low-grade to high-grade and may present with varying degrees of contrast enhancement and edema.
• Ganglioglioma: A rare type of brain tumor that is composed of both neuronal and glial cells. Gangliogliomas often present with a characteristic "soap bubble" appearance on imaging studies.
• Dysembryoplastic Neuroepithelial Tumor (DNET): A rare type of brain tumor that typically presents in the temporal lobe, often associated with seizures.

Key Imaging Features to Consider:

• Calcifications
• Contrast enhancement patterns
• Edema and mass effect
• Location within the brain

Clinical Presentation:

• Seizures are a common presenting symptom for mixed gliomas.
• Other symptoms may include headache, nausea, vomiting, and changes in mental status.

References:

• [8] Mixed glioma is a subset of brain tumors that show characteristics of both astrocytoma and oligodendroglioma. The term "Oligoastrocytoma" is considered outdated ...
• [9] Jul 2, 2008 — The differential diagnosis for these cortical based tumors includes oligodendroglioma, ganglioglioma and Dysembryoplastic Neuroepithial Tumor ( ...