Atypical Teratoid Rhabdoid Tumor

• ATRT is a rare, highly aggressive brain and spinal cord tumor predominantly affecting infants and young children.
• It is often linked to genetic mutations, primarily in the SMARCB1 gene.
• Symptoms vary widely based on tumor location but can include increased head circumference, vomiting, and developmental delays.
• Diagnosis typically involves advanced imaging, a tissue biopsy, and genetic testing.
• Treatment is multi-modal, combining surgery, chemotherapy, and sometimes radiation therapy, with a generally guarded prognosis.

What is Atypical Teratoid Rhabdoid Tumor?

What is Atypical Teratoid Rhabdoid Tumor? It is a rare, fast-growing tumor of the central nervous system (CNS) that can develop in the brain, spinal cord, or, less commonly, other parts of the body. This aggressive cancer is most frequently diagnosed in children under the age of three. ATRT is distinguished by its unique cellular characteristics, including rhabdoid cells, and a strong association with specific genetic alterations. The vast majority of ATRT cases are linked to mutations in the SMARCB1 gene (also known as INI1), or, in rare instances, the SMARCA4 gene. According to the American Brain Tumor Association, ATRT accounts for approximately 1-2% of all pediatric brain tumors, but it represents a higher percentage, up to 10%, of brain tumors in infants under one year of age.

Recognizing ATRT: Symptoms and Diagnosis

Recognizing atypical teratoid rhabdoid tumor symptoms can be challenging due to their non-specific nature and dependence on the tumor’s location and size within the brain or spinal cord. In infants, common signs often include:

• A rapidly increasing head circumference, frequently caused by hydrocephalus (fluid buildup).
• Persistent vomiting, often accompanied by poor feeding.
• Unusual irritability, lethargy, or changes in alertness.
• Developmental delays or a regression in achieved milestones.

In older children, symptoms might present as recurrent headaches, vision problems, balance issues, or new-onset seizures. The diagnostic process typically begins with advanced imaging techniques, primarily Magnetic Resonance Imaging (MRI) of the brain and spine, which helps identify the tumor’s presence and extent. A definitive diagnosis requires a tissue biopsy, usually performed during surgery, followed by a pathological examination to confirm the presence of characteristic rhabdoid cells. Genetic testing for SMARCB1 or SMARCA4 mutations is crucial for confirming the diagnosis and guiding treatment strategies.

ATRT Treatment Options and Outlook

Due to the aggressive nature of this tumor, atypical teratoid rhabdoid tumor treatment options are intensive and multi-modal. The primary goal is to remove as much of the tumor as safely possible through surgical resection. Following surgery, patients typically undergo aggressive chemotherapy regimens, which may include high-dose chemotherapy with stem cell rescue to combat the tumor’s rapid growth and spread. Radiation therapy, such as proton therapy, may also be considered, particularly for children over three years old, as radiation in very young children carries significant risks to developing brain tissue. Emerging therapies, including targeted molecular therapies and immunotherapies, are continually being explored in clinical trials to improve outcomes.

The atypical teratoid rhabdoid tumor prognosis remains guarded, especially for infants and those with metastatic disease at diagnosis. While challenging, advancements in treatment protocols have led to improved outcomes compared to historical data. However, survival rates can vary significantly based on factors such as the child’s age at diagnosis, the tumor’s location, and the extent of surgical removal. Ongoing research aims to develop more effective and less toxic treatments to improve the long-term outlook for children diagnosed with ATRT.