Atypical Teratoid Rhabdoid Tumor (ATRT)

Atypical Teratoid Rhabdoid Tumor, also referred to as ATRT, is a rare, high-grade tumor that occur most often in children age 3 and younger. They can appear as a large, bulky mass, tend to be fast-growing, and may spread through the central nervous system.

Location

ATRTs can occur anywhere in the brain or spinal cord.

Symptoms

Symptoms depend on the age of the patient as well as the size and location of the tumor. These may include nausea and vomiting, unusual sleepiness or change in activity level, loss of balance, lack of coordination, trouble walking, headache, seizures, and increased head size or bulging fontanelle (in infants).

Treatment

Treatment generally involves surgery to remove the tumor followed by intensive chemotherapy. Radiation is often utilized depending on the age of the patient and if the tumor has spread.

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.

Survival in ATRT is dependent on age at diagnosis, extent of surgery, therapy utilized, presence of rhabdoid tumor predisposition syndrome, and if the tumor has spread. The poorest survival is in young infants and patients with metastatic disease; in contrast, the highest survival is in children ≥3 years old at diagnosis without metastatic disease treated with aggressive surgical resection, chemotherapy, and radiation therapy.

The 5-year relative survival rates for ATRT by age group are as follows:

Children (ages 0-14): 47.8%
Adolescents and Young Adults (ages 15-39): 41.5%
Adults (ages 40+): 24.6%

Incidence

ATRTs are a very rare tumor, accounting for less than 100 cases per year. However, they comprise up to 50% of central nervous system tumors diagnosed in children in their first year of life.

Age Distribution

ATRT occur most commonly in children 3 years or younger at diagnosis with the majority of patients diagnosed in their 2nd year of life.

Risk Factors

Up to a third of patients with ATRT have a germline mutation (a change in the genes in all cells of their body, not just in the tumor) in either the SMARCB1 gene (more common) or the SMARCA4 gene. The presence of either of these germline mutations is diagnostic of rhabdoid tumor predisposition syndrome and puts patients at much higher risk for development of a rhabdoid tumor in either the brain (called ATRT) or elsewhere in the body (called malignant rhabdoid tumor).

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.

More than 95% of ATRTs are characterized by an inactivating mutation or deletion in the gene SMARCB1 (also known as INI1), while the remainder have a similar change in the gene SMARCA4. These tumors rarely have any additional shared mutations or genetic changes.

Three molecular subgroups of ATRT have been identified: ATRT-MYC, ATRT-SHH, and ATRT-TYR. These subgroups differ in age of onset, location, and incidence of metastases; current and planned studies are assessing if there are differences in response to therapy and survival between these molecular subgroups.

Additional Resources

Content last reviewed:

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