From MedlinePlus Genetics
Rhabdoid tumor predisposition syndrome (RTPS) is characterized by a high risk of developing cancerous (malignant) growths called rhabdoid tumors. These highly aggressive tumors are called rhabdoid because their cells resemble rhabdomyoblasts, which are cells that are normally found in embryos before birth and develop into muscles used for movement (skeletal muscles).

Rhabdoid tumors are rare in the general population. They usually occur in the first year of life, and are much less likely to appear after age 4. In people with RTPS, the tumors occur at an average age of 4 to 7 months, and can even occur before birth. Affected individuals may have multifocal synchronous tumors, which means that multiple tumors that develop independently (primary tumors) occur at the same time. The rhabdoid tumors that occur in RTPS usually grow and spread more quickly than those in children without this predisposition, and affected individuals often do not survive past childhood.

More than half of all malignant rhabdoid tumors (MRTs) develop in the cerebellum, which is the part of the brain that coordinates movement. Rhabdoid tumors in the brain and spinal cord (central nervous system) are called atypical teratoid/rhabdoid tumors (AT/RTs).

Tumors other than rhabdoid tumors can also occur in people with RTPS. Some affected children develop noncancerous (benign) tumors called schwannomas, which grow on nerve cells. Women with RTPS are at increased risk of developing a rare type of ovarian cancer called small cell cancer of the ovary hypercalcemic type (SCCOHT).

Rhabdoid tumors also occur outside the central nervous system. These tumors include rhabdoid tumors of the kidneys (RTKs) and tumors that develop in other organs and tissues of the body (called extrarenal malignant rhabdoid tumors or eMRTs). The type of rhabdoid tumor can vary among individuals with RTPS, even within the same family.  https://medlineplus.gov/genetics/condition/rhabdoid-tumor-predisposition-syndrome