Central Nervous System (CNS) Embryonal Tumor and Tumors of Uncertain Differentiation Treatment

Many brain and spinal cord tumors are rare and aggressive but difficult to categorize. In the past, these tumors have gone by several names, including:

• Primitive neuroectodermal tumors (PNETs)
• Malignant neuroepithelial tumors
• High-grade neuroepithelial tumors
• Rare CNS embryonal tumors
• Mesenchymal tumors
• CNS primary sarcomas

If your child has been diagnosed with any of these, you have come to the right place. We will guide you to a better understanding of their diagnosis.

These tumors look similar under the microscope. But we have recently learned that the molecular changes (genetic mutations) that make these tumors grow are quite different. Most of the new names are now defined by the molecular features. This may be confusing. Also, the typical age at diagnosis, the prognosis, and the treatment plan may differ based on the molecular markers.

These tumors are all aggressive. Each responds differently to treatment. We are redefining how to treat these tumors. We intensify and change the therapy for the most aggressive tumors. For those with a better prognosis, we can decrease therapy. This reduces side effects.

Types of CNS embryonal tumors and tumors of uncertain differentiation

These tumors are now categorized to include multiple types based on the molecular or genetic changes (mutations) that caused the tumor to develop.

Because there are different types, molecular testing must occur on the tumor to get the correct diagnosis and determine the best treatment.

Types may include:

• Astroblastoma, MN1 altered
• Atypical teratoid rhabdoid tumor (ATRT)
• CIC rearranged sarcoma
• CNS embryonal tumor, not otherwise specified/not elsewhere classified (NOS/NEC)
• CNS Ewing sarcoma
• CNS neuroblastoma, FOXR2 activated
• CNS tumor with BCOR ITD
• Embryonal tumor with multilayer rosettes (ETMR)
• Intracranial mesenchymal tumor
• Pineal parenchymal tumors, which include:
  • Pineoblastoma
  • Pineal parenchymal tumor of intermediate differentiation (PPTID)
  • Papillary tumor of the pineal region (PTPR)
  • Pineocytoma
  • Desmoplastic myxoid tumor of the pineal region.
• Primary intracranial sarcoma, DICER1-mutant

Treatment of CNS embryonal tumors and tumors of uncertain differentiation

Treatment may include surgery followed by radiation and chemotherapy:

• Surgery removes part or all of the tumor tissue. This takes out cancerous tissue and helps determine the type of tumor.
• Radiation is an important part of treatment for all of these tumors. The dose, location, and timing of radiation will depend on many factors. These include your child’s age, type of tumor, and if it has spread to other parts of the brain or spine.
• Chemotherapy (chemo) is important in the treatment of these tumors. The exact type of chemotherapy and the length of treatment will depend on your child’s age and type of tumor.

CNS embryonal tumors and tumors of uncertain differentiation prognosis 

The prognosis for different embryonal tumors varies greatly. It depends on:

• The specific type and genetic mutations
• If the tumor was totally removed (resected)
• If the tumor is just in 1 area or if it has spread
• The child’s age
• If the tumor was newly diagnosed or has returned (recurred)

CNS embryonal tumors and tumors of uncertain differentiation clinical trials 

Patients with these tumors take part in clinical trials that use the most advanced diagnosis tools and treatments available. Our goal is to give each child the best treatment with the lowest number of side effects.

Our doctors and scientists work together to find better ways to treat patients. In many cases, new treatments are being developed right here on the St. Jude campus.

We also take part in trials developed by the Children’s Oncology Group (COG) and the Pediatric Brain Tumor Consortium (PBTC). Many of our doctors and scientists play key roles in developing these large studies. They happen at centers across the United States.

If a clinical trial is unavailable, your child may have therapies commonly used to treat patients with brain or spine tumors. These are often referred to as “standard” treatment. If they do not work, patients may be eligible to enter clinical trials using new therapies or existing therapies in a new way.

Learn more about clinical research at St. Jude.