This is a medical question of type : information 
 What is (are) Childhood Central Nervous System Embryonal Tumors ? 
 Key Points 
                    - Central nervous system (CNS) embryonal tumors may begin in embryonic (fetal) cells that remain in the brain after birth.     - There are different types of CNS embryonal tumors.    - Pineoblastomas form in cells of the pineal gland.    - Certain genetic conditions increase the risk of childhood CNS embryonal tumors.    - Signs and symptoms of childhood CNS embryonal tumors or pineoblastomas depend on the child's age and where the tumor is.    - Tests that examine the brain and spinal cord are used to detect (find) childhood CNS embryonal tumors or pineoblastomas.     - A biopsy may be done to be sure of the diagnosis of CNS embryonal tumor or pineoblastoma.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                
                
                    Central nervous system (CNS) embryonal tumors may begin in embryonic (fetal) cells that remain in the brain after birth.
                    Central nervous system (CNS) embryonal tumors form in embryonic cells that remain in the brain after birth. CNS embryonal tumors tend to spread through the cerebrospinal fluid (CSF) to other parts of the brain and spinal cord.   The tumors may be malignant (cancer) or benign (not cancer). Most CNS embryonal tumors in children are malignant. Malignant brain tumors are likely to grow quickly and spread into other parts of the brain. When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Benign brain tumors grow and press on nearby areas of the brain. They rarely spread to other parts of the brain. Both benign and malignant brain tumors can cause signs or symptoms and need treatment.   Although cancer is rare in children, brain tumors are the third most common type of childhood cancer, after leukemia and lymphoma. This summary is about the treatment of primary brain tumors (tumors that begin in the brain). The treatment of metastatic brain tumors, which begin in other parts of the body and spread to the brain, is not discussed in this summary. For information about the different types of brain and spinal cord tumors, see the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview.   Brain tumors occur in both children and adults. Treatment for adults may be different from treatment for children. See the PDQ summary on Adult Central Nervous System Tumors Treatment for more information on the treatment of adults.
                
                
                    There are different types of CNS embryonal tumors.
                    The different types of CNS embryonal tumors include:         -  Medulloblastomas  Most CNS embryonal tumors are medulloblastomas. Medulloblastomas are fast-growing tumors that form in brain cells in the cerebellum. The cerebellum is at the lower back part of the brain between the cerebrum and the brain stem. The cerebellum controls movement, balance, and posture. Medulloblastomas sometimes spread to the bone, bone marrow, lung, or other parts of the body, but this is rare.      -  Nonmedulloblastoma embryonal tumors  Nonmedulloblastoma embryonal tumors are fast-growing tumors that usually form in brain cells in the cerebrum. The cerebrum is at the top of the head and is the largest part of the brain. The cerebrum controls thinking, learning, problem-solving, emotions, speech, reading, writing, and voluntary movement. Nonmedulloblastoma embryonal tumors may also form in the brain stem or spinal cord.  There are four types of nonmedulloblastoma embryonal tumors:                  -  Embryonal tumors with multilayered rosettes  Embryonal tumors with multilayered rosettes (ETMR) are rare tumors that form in the brain and spinal cord. ETMR most commonly occur in young children and are fast-growing tumors.        -  Medulloepitheliomas  Medulloepitheliomas are fast-growing tumors that usually form in the brain, spinal cord or nerves just outside the spinal column. They occur most often in infants and young children.        -  CNS neuroblastomas  CNS neuroblastomas are a very rare type of neuroblastoma that form in the nerve tissue of the cerebrum or the layers of tissue that cover the brain and spinal cord. CNS neuroblastomas may be large and spread to other parts of the brain or spinal cord.        -  CNS ganglioneuroblastomas  CNS ganglioneuroblastomas are rare tumors that form in nerve tissue of the brain and spinal cord. They may form in one area and be fast growing or form in more than one area and be slow growing.                      Childhood CNS atypical teratoid/rhabdoid tumor is also a type of embryonal tumor, but it is treated differently than other childhood CNS embryonal tumors. See the PDQ summary on Childhood Central Nervous System Atypical Teratoid/Rhabdoid Tumor Treatment for more information.
                
                
                    Pineoblastomas form in cells of the pineal gland.
                    The pineal gland is a tiny organ in the center of the brain. The gland makes melatonin, a substance that helps control our sleep cycle.    Pineoblastomas form in cells of the pineal gland and are usually malignant. Pineoblastomas are fast-growing tumors with cells that look very different from normal pineal gland cells. Pineoblastomas are not a type of CNS embryonal tumor but treatment for them is a lot like treatment for CNS embryonal tumors.   Pineoblastoma is linked with inherited changes in the retinoblastoma (RB1) gene. A child with the inherited form of retinoblastoma (cancer than forms in the tissues of the retina) has an increased risk of pineoblastoma. When retinoblastoma forms at the same time as a tumor in or near the pineal gland, it is called trilateral retinoblastoma. MRI (magnetic resonance imaging) testing in children with retinoblastoma may detect pineoblastoma at an early stage when it can be treated successfully.