Brain and other nervous system cancers are the second most common cancers in children, making up about 22% of childhood cancers. Most brain cancers of children involve the cerebellum or brain stem. In early stages they can cause headaches, nausea, vomiting, blurred or double vision, dizziness, and trouble walking or handling objects. Adults are more likely to develop cancers in different parts of the brain--usually the cerebral hemispheres. Spinal cord tumors are less common than brain tumors in both children and adults.

Neuroblastoma is the most common extracranial (outside of the brain) solid tumor in children and most often diagnosed during the first year of life. This tumor can appear anywhere but usually occurs in the abdomen (stomach) as a swelling. It accounts for about 7% of childhood cancers.

Wilms tumor is a cancer that may affect one or both kidneys. It is most often found in children between 2 and 3 years old, and may be recognized by a swelling or lump in the belly (abdomen.) It accounts for about 6% of childhood cancers.

Non-Hodgkin lymphoma and Hodgkin lymphoma, (sometimes called Hodgkin disease, Hodgkin's disease, or Hodgkin's lymphoma), are cancers that start in lymph nodes. These cancers may spread to bone marrow and other organs. They also can cause fever, weakness, and swelling of lymph nodes ("glands") in the neck, armpit, or groin. Hodgkin lymphoma can occur in both children and adults, and accounts for about 4% of childhood cancers. It is more common, though, in 2 age groups: early adulthood (age 15 to 40, usually 25 to 30) and late adulthood (after age 55). Hodgkin lymphoma is rare before 5 years of age. About 10% to 15% of cases are diagnosed in children 16 years of age and younger.

Rhabdomyosarcoma is the most common soft tissue sarcoma in children, and makes up about 3% of childhood cancers. The tumor originates from the same embryonic cells that develop into striated (voluntary) muscles. It can happen in the head and neck, groin, trunk, arms and legs. It may cause pain, swelling (lump), or both.

Retinoblastoma is a cancer of the eye. Although relatively rare, it accounts for less than 3% of childhood cancers and about 5% of childhood blindness. It usually occurs in children under the age of 4.

Bone Cancers: The incidence of primary bone cancer (cancers that started in the bones) is highest in children and adolescents. Primary bone cancer is different from metastatic bone cancer, which is cancer that has spread to the bone. Metastatic bone cancer is named for the place the cancer came from. For instance, it might be described as prostate cancer that has spread (metastasized) to the bone, or breast cancer with bone metastasis. Metastatic bone cancer is more common than primary bone cancer because many types of cancer can spread to the bone. There are 2 types of primary bone cancers that happen in children:

Osteosarcoma is uncommon, comprising a little over 2% of all new childhood cancer cases in the United States. It often causes no pain or symptoms until swelling starts.

Ewing sarcoma is a less common primary bone cancer that occurs mostly in children and adolescents. It accounts for a little more than 1% of childhood cancers.