How do you classify retinoblastoma?

Intraocular retinoblastomas are classified as Group A through E, based on the extent of the tumor growth and the cancer’s effects on the eye. The group classification also indicates the chance that the affected eye or eyes can be saved with treatment.

What are the different types of retinoblastoma?

Types of Retinoblastoma

• Unilateral retinoblastoma affects one eye and accounts for 60% to 75% of cases.
• Bilateral retinoblastoma affects both eyes.
• PNET (primitive neuroectodermal tumors) retinoblastoma occurs when an associated tumor forms in primitive nerve cells in the brain.
• Learn more about retinoblastoma:

What type of gene is the retinoblastoma gene?

The most important gene in retinoblastoma is the RB1 tumor suppressor gene. This gene makes a protein (pRb) that helps stop cells from growing too quickly. Each cell normally has two RB1 genes. As long as a retinal cell has at least one RB1 gene that works as it should, it will not form a retinoblastoma.

What is bilateral retinoblastoma?

About 40% of children develop tumours in both eyes. This is known as bilateral retinoblastoma. The cancer does not spread from one eye to the other. When both eyes are affected and / or multiple tumours form, each tumour arises from a unique retinal cell.

What are the differential diagnosis of retinoblastoma?

However, the differential diagnosis includes other entities such as a cataract, Coats’ disease, retinopathy of prematurity, toxocariasis, choroidal coloboma, vitreous hemorrhage, myelinated retinal nerve fibers, and other retinal tumors such as astrocytic hamartoma.

Is retinoblastoma recessive or dominant?

Hereditary retinoblastoma is passed from parents to children in an autosomal dominant pattern, which means only one parent needs a single copy of the mutated gene to pass the increased risk of retinoblastoma on to the children.

What is the difference between unilateral and bilateral retinoblastoma?

The retinoblastoma tumor(s) originate in the retina, the light sensitive layer of the eye that enables the eye to see. When the tumors are present in one eye, it is referred to as unilateral retinoblastoma, and when it occurs in both eyes it is referred to as bilateral retinoblastoma.

Is retinoblastoma unilateral or bilateral?

Retinoblastoma is bilateral in about 40% of cases with a median age at diagnosis of one year. All bilateral and multifocal unilateral forms are hereditary.

What percentage of retinoblastoma is hereditary?

Approximately 60 percent of cases of retinoblastoma are non-heritable and 40 percent are heritable. All of the non-heritable cases affect only one eye (unilateral). Of the 40 percent of cases that are heritable, approximately 85 percent of patients will develop multiple tumors affecting both eyes (bilateral).

What is the International Classification of retinoblastoma?

Thus, the International Classification of Retinoblastoma (ICRB) (see Table 2) was developed to better predict those with intraocular retinoblastoma who are likely to be cured without the need for enucleation or external-beam radiation treatment: Small intraretinal tumors (< 3mm) away from foveola and disc.

Is retinoblastoma hereditary?

For decades, it has been known that there is a genetic component to this condition. The retinoblastoma susceptibility gene RB1 is a tumor-suppressing gene. It encodes a protein with a regulatory function in the cellular growth cycle at the G1 checkpoint.

What is the retinoblastoma susceptibility gene RB1?

The retinoblastoma susceptibility gene RB1 is a tumor-suppressing gene. It encodes a protein with a regulatory function in the cellular growth cycle at the G1 checkpoint. It is located on subband 13q14.2. Both alleles of the retinoblastoma gene have to be inactivated for tumor development.

What is retinoblastoma pathognomonic aberration?

Retinoblastoma is the most common primary intraocular malignancy of childhood. It typically presents with leukocoria or strabismus. In later stages of the disease, the child may exhibit proptosis, buphthalmos, or hypopyon. The pathognomonic molecular aberration is a loss of function mutation in the …