Extra-Cranial Malignant Rhabdoid Tumor (MRT)
What is extra-cranial malignant rhabdoid tumor?
Rhabdoid tumor is a type of tumor that is made up of many large cells. Some rhabdoid tumors can grow in the brain, and these are called atypical teratoid rhabdoid tumors (ATRT). Most often, they grow in the kidneys and other soft tissues, like the muscles attached to the bones of the skeleton. Rhaboid tumors that grow outside of the brain are called extra-cranial malignant rhabdoid tumor, malignant rhabdoid tumor, or MRT. MRTs grow and spread to other parts of the body quickly.
How common are extra-cranial malignant rhabdoid tumors?
MRT is very rare. Some studies estimate that less than one person for every one million people has this type of rare tumor. It is most common in babies between 11 and 18 months old.
How are extra-cranial malignant rhabdoid tumors diagnosed?
MRTs sometimes look like other tumors. Doctors use a few different tests to diagnose MRT.
Imaging: Doctors use imaging scans such as MRI, ultrasound, and CT to get a look at where the tumor is in the body and how big it is.
Biopsy: To check if the tumor is MRT, your child’s doctor will do a biopsy, taking a small sample from the tumor with a needle. An expert, called a pathologist, will study cells from the sample under the microscope to see what kind of tumor it is. They may also test the cells to see if there are changes in the gene called SMARCB1. Almost all rhabdoid tumors have changes in the SMARCB1 gene.
How are extra-cranial malignant rhabdoid tumors treated?
Studies have shown that using many different types of treatments can be better at killing the tumor cells than one treatment alone.
Surgery: Surgery is used to remove as much of the cancer as possible. Sometimes, doctors can remove the entire tumor in one piece.
Radiation Therapy: Radiation therapy uses radiation to kill tumor cells and shrink the tumor.
High Dose Chemotherapy: High dose chemotherapy uses drugs to kill the fast-growing tumor cells. This may have side effects.
Do extra-cranial malignant rhabdoid tumors run in families?
No, MRT does not run in families.
How do extra-cranial malignant rhabdoid tumors form?
We know that in most cases of MRT, there is a change in the DNA in a gene called SMARCB1, so it may be very important for how these tumors form. Scientists are trying to figure out how this works so they can invent new treatments.
What is the prognosis for someone with extra-cranial malignant rhabdoid tumors?
The estimate of how a disease will affect you long-term is called prognosis. Every person is different and prognosis will depend on many factors, such as:
- Where the tumor is in your body
- If the cancer has spread to other parts of your body
- How much of the tumor was taken out during surgery
If you want information on your child’s prognosis, it is important to talk to your child’s doctor. NCI also has resources to help you understand cancer prognosis.
The prognosis of children with MRT is very poor. Although there are a few cases of long-term survival, most children do not live longer than a few years. Children diagnosed after the age of 2 tend to have a better prognosis than those who are diagnosed when they are younger. Keep in mind that doctors estimate MRT survival rates by how groups of children with these tumors have done in the past. Because there are so few children with MRT, these rates may not be very accurate.
It is very important to work with a team of experts as soon as possible after diagnosis to improve your child’s chances of survival.