Gangliogliomas are rare types of tumours that generally develop in the central nervous system (CNS). More specifically, they develop from ganglia in the CNS, which are a group of neuronal bodies which sends messages to the brain relating to touch, smell, taste, sound, and visual stimuli. While gangliogliomas are generally benign (non-cancerous), in rare cases they may become malignant (cancerous).

The brain is a complex organ that is responsible for controlling all functions of the body. It has five main portions: the cerebrum, cerebellum, brainstem, pituitary gland, and hypothalamus. The cerebrum is the biggest part of the brain, and consists of the frontal, parietal, temporal, and occipital lobes. This part of the brain is responsible for voluntary movement, intelligence, and memory. The cerebellum is a small part of the brain located at the back of the head, and regulates posture and balance. The brainstem is a small, stalk-like structure towards the bottom of the brain that connects the brain to the spinal cord.  It regulates many vital bodily processes, such as swallowing, breathing, and heart rate. The pituitary gland is a pea sized organ located behind the eyes, and is responsible for the production and secretion of hormones in the body. The hypothalamus is located deep within the brain, and has many important functions, such as producing and secreting different hormones, regulating temperature, and controlling appetite.

The spinal cord is a long, thin, tubular structure that extends down from the brainstem to the lower back. It is made of nerve tissue, and is surrounded by the bones of the spine (vertebrae). The spinal cord is responsible for transmitting nerve signals from the brain to the body, and vice versa. It has motor functions (such as voluntary movement), sensory functions (such as pressure, touch, temperature, and pain), and autonomous functions (such as regulating digestion, heart rate, and blood pressure).

Gangliogliomas are most commonly found in the temporal lobe of the cerebrum, but can also develop in the cerebellum, brainstem, and spinal cord. Initially, they may be confused with gangliocytomas as they are indistinguishable on imaging scans.

Gangliogliomas are generally diagnosed equally among the sexes, and are most commonly found in people between the ages of 10-30. However, anyone can develop this disease.

Types of Gangliogliomas

Because of how rare gangliogliomas are, very few subtypes of this disease have been identified.

Desmoplastic Infantile Ganglioglioma (DIG)

Desmoplastic infantile ganglioglioma (DIG) is a very rare form of ganglioglioma that is generally diagnosed in children, often males, under two years old. It is generally classified as a grade I or benign tumour, and is often found in the cerebrum. DIGs are usually slow growing, and can have a good prognosis when found early.

Anaplastic Ganglioglioma

Anaplastic gangliogliomas are rare cancers that is generally classified as a grade III or malignant tumour. They are most commonly found in the temporal lobe of the brain, however they can develop anywhere in the CNS. These tumours are often aggressive, likely to recur, and may not have as good of a prognosis as DIG.

Treatment 

When cancers are detected, they are staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body), and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, brain cancers are rarely staged, as they rarely spread to other parts of the body. Instead, they are generally graded from I-III.

Gangliogliomas are often graded by subtype:

• Grade 1 (low grade) tumours: cancer cells present as slightly abnormal and are usually slow growing. Includes DIGs.
• Grade II (intermediate grade) tumours: cancer cells present as abnormal and grow faster than grade-I tumours. So far, no variants of gangliogliomas are classified as grade II tumours.
• Grade III (high grade) tumours: cancer cells present as very abnormal and grow quickly. Includes anaplastic ganglioglioma.

Once your tumour has been graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.

Treatment is dependent on several factors, including location, age, stage of disease and overall health.

Treatment options for gangliocytomas may include:

• Surgery to remove as much of the tumour as possible.
• Watch and wait.
• Chemotherapy.
• Radiation therapy.
• Clinical trials.
• Palliative care. 

For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.  

Risk factors 

Because of how rare gangliogliomas are, there has been limited research done into the risk factors of this disease.

Early symptoms 

Gangliogliomas may appear asymptomatic in the early stages of disease. As the tumour progresses, some of the following symptoms may appear:

• Epilepsy (most commonly temporal lobe epilepsy (TLE)).
• Increased intracranial pressure.
• Hydrocephalus. 
• Headaches, generally worse in the morning.
• Blurred or double vision.
• Nausea and/or vomiting (often worse in the morning).
• General feeling of weakness.
• Behavioural changes.
• Difficulties with moving and/or talking.
• Lack of energy.
• Fatigue.
• Increased blood pressure.
• Confusion and/or lack of alertness.

Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned. 

Diagnosis/diagnosing 

If your doctor suspects you have an gangliocytoma, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment.

Physical examination

Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.

Neurological examination

A neurological examination assesses sensory and motor functions, and can generally be done in your GPs office. The doctor may check your vision, hearing, balance, coordination, strength and reflexes, depending on the signs and symptoms you have described. Any problem that is detected in this exam can help determine which portion of the CNS needs further investigation.

Imaging & blood tests

The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-rays, bone scan and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.

Biopsy

Once the location of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. This may be done during a surgery, or by a stereotactic needle biopsy. This sample will then be sent to the lab for analysis.

Prognosis (Certain factors affect the prognosis and treatment options) 

While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, low-grade gangliogliomas have a good prognosis and survival rates. However, if the tumour has become malignant and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.

References 

• Dana-Farber Cancer Institute
• National Organisation for Rare Disorders (NORD) – Anaplastic Ganglioglioma
• Radiopaedia – Desmoplastic Infantile Ganglioglioma
• Radiopaedia - Ganglioglioma

^{Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.}