Short answer · Medically reviewed summary · Last updated: 2026-04-07

Retinoblastoma is a rare form of eye cancer that develops in the retina, the light-sensitive tissue at the back of the eye, typically occurring in young children. It arises from genetic mutations in retinal cells that cause them to grow uncontrollably, and it requires prompt medical evaluation to preserve vision and, most importantly, the child's life. What exactly is Retinoblastoma? Retinoblastoma is a malignant tumor that originates in the retina.

What is Retinoblastoma

Name: What is Retinoblastoma
Creator: DiseaseMaps Editorial Team
Published: 2015-09-16UTC22:59:20.0000000

What is Retinoblastoma? Plain-language, medically reviewed definition plus the lived reality told by patients.

Retinoblastoma is a rare form of eye cancer that develops in the retina, the light-sensitive tissue at the back of the eye, typically occurring in young children. It arises from genetic mutations in retinal cells that cause them to grow uncontrollably, and it requires prompt medical evaluation to preserve vision and, most importantly, the child's life.

What exactly is Retinoblastoma?

Retinoblastoma is a malignant tumor that originates in the retina. It is the most common primary intraocular malignancy in childhood. The condition occurs when nerve cells in the retina develop genetic mutations that cause them to grow and multiply rapidly instead of dying, forming a mass of cancer cells. While it primarily affects the eye, if left untreated, retinoblastoma can spread (metastasize) to other parts of the body, including the brain and bone marrow.

How common is Retinoblastoma and who is affected?

Retinoblastoma is considered a rare disease, with an estimated global incidence of approximately 1 in 15,000 to 1 in 20,000 live births. It is almost exclusively a disease of early childhood, with the average age of diagnosis being between 18 and 24 months. By the age of five, the vast majority of cases have been identified. Retinoblastoma affects boys and girls equally, and there is no significant difference in prevalence based on race or geographic location.

What are the two main types of Retinoblastoma?

Clinicians generally classify retinoblastoma based on whether the genetic mutation is present in all body cells or confined only to the eye:

Heritable (Germline) Retinoblastoma: This occurs when the mutation is present in every cell of the body. These children are at risk of developing tumors in both eyes (bilateral) and have a higher risk of developing other types of cancer later in life.

Non-heritable (Somatic) Retinoblastoma: This accounts for about 60% of cases. The mutation occurs only in the retinal cells of one eye (unilateral), and there is no increased risk of passing the condition to offspring or developing secondary cancers elsewhere.

How does the underlying mechanism work?

The development of retinoblastoma is linked to the RB1 gene located on chromosome 13. This gene acts as a "tumor suppressor," meaning its job is to control cell division. When both copies of the RB1 gene are mutated or missing, the cell loses its "brakes" and begins to divide uncontrollably. In hereditary cases, the child inherits one mutated copy from a parent and acquires the second mutation later; in non-hereditary cases, both mutations occur spontaneously in the retinal cells during early development.

What differentiates Retinoblastoma from other eye conditions?

Unlike common childhood eye issues like strabismus (crossed eyes) or cataracts, retinoblastoma often presents with a distinct clinical sign known as leukocoria—a white or "cat's eye" reflection in the pupil, often visible in flash photography. While other conditions may mimic these symptoms, any unusual reflection or change in a child’s pupil requires immediate assessment by an ophthalmologist to rule out retinoblastoma.

Next steps

Consult a specialist: If you notice unusual white reflections in your child's eyes or changes in vision, consult a pediatric ophthalmologist or an ocular oncologist immediately.

Genetic Counseling: Families should seek a referral to a clinical geneticist to determine if the condition is hereditary and to understand risks for other family members.

Join the community: Connect with others at DiseaseMaps.org to share experiences and find support among the 8 members already navigating this journey.

Stay informed: Follow updates from reputable organizations like the American Academy of Ophthalmology or the Retinoblastoma International foundation.

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.