Diffuse Intrinsic Pontine Glioma (DIPG)

Diffuse intrinsic pontine glioma, referred to as DIPG, is a malignant (cancerous) glial tumor of the brainstem that occurs almost exclusively in childhood. Unfortunately, despite decades of research, prognosis for this tumor remains poor.

Location

DIPG occurs within the brainstem, the portion of the brain that controls many critical functions integral to life including breathing.

Symptoms

The most common symptoms of DIPG include cranial nerve abnormalities (crossed eyes or lazy eye, drooping eye lids, double vision, difficulty swallowing), difficulty walking, balance issues, and arm or leg weakness. Patients usually seek medical attention one month or less from the start of symptoms. The diagnosis of DIPG can often be made with imaging (i.e., MRI) alone without the need for a surgical biopsy.

Treatment

Due to the location of the tumor within the brainstem and the shape of the tumor (no clear tumor border), complete or partial surgical removal is not feasible in DIPG.

However, tumor biopsies may be performed in some patients to assess for molecular features. Certain molecular features offer additional treatment options including medications or clinical trials.

Radiation therapy is the only treatment that has shown benefit in DIPG. There are numerous clinical trials for DIPGs, both at the time of diagnosis (with or following radiation) or at the time of disease progression.

Prognosis

Prognosis means a prediction of outcome. This information is usually based on information gathered from groups of people with the same disease. It is important to remember these statistics are not individualized.

Even with treatment with radiation, the median survival of patients with DIPG is less than 1 year from diagnosis, with over 99% of patients dying of the disease within 5 years after diagnosis.

Incidence

Approximately 300 children are diagnosed with DIPG in the United States each year. DIPGs comprise approximately 10% of pediatric brain tumors but represent 80% of pediatric tumors occurring in the brainstem.

Age Distribution

The most common age at diagnosis is 5-9 years old. DIPG is extremely rare in adults.

Risk Factors

There are no known risk factors for developing DIPG.

Molecular Profile

Molecular profiling is the detection of specific genes, proteins, or other molecules in a tumor. This information helps confirm tumor diagnosis, inform treatment options, and predict prognosis.

The majority of DIPGs (around 80%) have a characteristic mutation in the H3 protein known as H3K27M. Some DIPGs have mutations in other genes (ACVR1, TP53, or PPM1D) and/or the PI3K/AKT/mTOR signaling pathway. Unfortunately, at this time there are not medications that can target these molecular changes.

Additional Resources

Content last reviewed:

April 2022 by Holly B. Lindsay, MD, MS and Donald Williams (Will) Parsons, MD, PhD