Supratentorial primitive neuroectodermal (SPN) and pineal tumors are malignant growths that arise in the brain. SPN tumors develop from the outermost layer of cells in an embryo (the neuroectoderm) and are found in the upper portion of the brain (supratentorial). Normal neuroectodermal cells usually develop into the brain, spinal cord and nervous tissue. SPN and pineal tumors account for 3 to 8 percent of central nervous system tumors.
Tumors in the region of the pineal can also develop from the outer neuroectoderm but are found in or around the pineal gland, a tiny organ located in the central brain that secretes the hormone melatonin, which helps to control hormonal cycles and sleep-wake patterns.
Pineal tumors can also develop from germ cells, which are sex cells that eventually become eggs in females and sperm in males. Sometimes germ cells migrate to other parts of the body, such as the abdomen, chest and the brain. Once there, they may turn into a cancerous or benign growth called a germ cell tumor.
Pineal cancer may also arise from glial cells. Glial cells compise a network of branched fibers that support the tissue of the central nervous system.
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