Retinoblastomas are tumors that begin in the retina, the thin layer of tissue located on the back of the eyeball. If left untreated, the tumors can grow and fill most the eye.
Retinoblastomas make up three percent of pediatric cancers in children under the age of 15. Two-thirds of retinoblastoma cases are diagnosed before the patient is 2 years old.
There is a complex chain of events that leads to retinoblastoma, but it almost always begins with a change in the retinoblastoma (RB1) gene. Normally, this gene helps to keep cells from growing out of control, but a combination of factors can cause the gene to change and stop working correctly.
This RB1 gene mutation causes retinoblastoma to present in one of two forms: sporadic (non-hereditary) retinoblastoma or congenital (hereditary) retinoblastoma.
This type is not hereditary (passed down from parents to children) and occurs in 70-75 percent of cases. The abnormality develops in only in one eye, which means it’s easier to treat and there is less risk of cancer spreading to other areas.
This type occurs in 25-30 percent of cases. This mutation occurs during early development in the womb, or it is inherited (passed down) from a parent. Children with congenital (present at birth) retinoblastoma are at a higher risk of developing cancers in other areas because the RB1 gene that started the cancer is typically in all their cells.
A parent or physician typically notices that the child’s eye looks unusual. Additional retinoblastoma symptoms include:
- White pupillary reflex
- Lazy eye
- Pain in the eye
- Redness in the sclera (the white part of the eye)
- Bleeding in the front part of the eye
- Bulging eye
- A pupil (the dark part of the eye) that stays the same size when exposed to bright light
- A different color in the iris (the colored part of the eye)