What is Retinoblastoma?

Cancer can develop in the eyeball or in nearby structures, such as the eyelids or orbit. Tumors of the eye are most often metastatic tumors that have spread from other parts of the body. The most common primary cancers of the eyeball are melanomas of the eye and retinoblastomas. Retinoblastoma is the most common primary eye cancer in children, and forms in the retina, which contains cells that sense light and transmit signals through the optic nerve to the brain. The brain then interprets these signals as images. Retinoblastomas may develop at any age, but are most common in children under the age of 5. Retinoblastomas may be caused by a genetic mutation in chromosome 13. This genetic mutation may be passed on from parents to children, or it may occur spontaneously. A child with hereditary retinoblastoma is at an increased risk for developing trilateral retinoblastoma, in which cancer forms on the pineal gland in the middle of the brain. Retinoblastomas may form in one or both eyes, and in North America and Western Europe rarely spread from the eye to nearby tissue or other parts of the body. In developing countries, it is more common for the cancer to spread.