Diffuse Intrinsic Pontine Glioma (DIPG) is a highly aggressive and infiltrative brain tumor. While primarily recognized as a pediatric cancer, its occurrence in adults is extremely rare. This rarity presents unique challenges in diagnosis and management.
Understanding DIPG
DIPG develops in the pons, a part of the brainstem that controls many of the body’s essential functions, including breathing, heart rate, and movement. The tumor is “intrinsic,” meaning it grows within the brainstem itself, intertwining with healthy neural tissue rather than forming a distinct mass that can be easily removed. This infiltrative growth, combined with the pons’s critical role, makes surgical removal generally impossible. DIPG is characterized by rapid growth and a poor prognosis, making it one of the most challenging brain tumors to treat.
Unique Characteristics in Adults
DIPG in adults presents distinct features compared to its pediatric counterpart. While the median age for DIPG diagnosis in children is typically 6-9 years, adult cases have a median age at symptom onset of around 33.5 years. Genetic mutations, particularly the H3 K27M mutation, are prevalent in both pediatric and adult DIPG, found in about 37.2% of adult cases. Other mutations like IDH1 are also observed, occurring in approximately 26.5% of cases. The disease progression can sometimes be slower in adults compared to the rapid course seen in children. Despite this, adult DIPG remains highly aggressive. Its rarity also poses diagnostic challenges, potentially leading to delays in diagnosis.
Symptoms and Diagnosis
Adults with DIPG often experience neurological symptoms due to the tumor’s brainstem location. Common symptoms include cranial nerve deficits, such as double vision, facial weakness, or difficulty swallowing. Patients may also develop motor weakness, impacting limb strength and coordination, and issues with balance. Headaches are another frequently reported symptom. The diagnostic process typically begins with a thorough neurological examination to assess these symptoms. Magnetic Resonance Imaging (MRI) of the brain and spine is the primary imaging technique used to visualize the tumor and determine its extent. Due to the tumor’s sensitive location, a biopsy is often challenging and carries significant risks, so it may be avoided in favor of a clinical and radiological diagnosis. However, genomic testing for mutations like H3K27M and IDH is recommended for adult DIPG patients when a biopsy is performed.
Treatment and Management
Current treatment strategies for adult DIPG largely align with pediatric cases, with adjustments for adult physiology. Radiation therapy remains the primary approach, used to alleviate symptoms and achieve temporary tumor control. While it offers short-term benefits, its effects are generally temporary, and the tumor often progresses. Chemotherapy has shown limited effectiveness in treating DIPG, so its role is often restricted. Clinical trials exploring novel therapies and targeted agents are ongoing, offering hope for improved outcomes for adult patients. Supportive care, symptom management, and palliative care are also important, focusing on improving the patient’s quality of life.