Retinoblastoma

What it is

Retinoblastoma is the most common ocular malignancy found in children, and the average age of diagnosis is 18 months. In the paediatric tumour tables it is the one whose key feature is leukocoria, white pupil, with the age group given as under 3 yrs.

Causes and risk

It is caused by a loss of function of the retinoblastoma tumour suppressor gene on chromosome 13, and around 10% of cases are hereditary.

Named in full, the gene is RB1, a tumor suppressor at Chr13q14, and inheritance is autosomal dominant if familial. A family history of eye or limb removal in the family suggests germline RB1 mutation with bilateral or multifocal disease, and bilateral disease means RB1. Screening is done if there is a positive family history, and the tables add: screen siblings.

How it presents

Absence of red-reflex, replaced by a white pupil, leukocoria, is the most common presenting symptom. With it: strabismus and visual problems.

Put as clues: age < 2 years is the peak incidence of retinoblastoma, leukocoria is the classic sign of intraocular tumor, family history of eye or limb removal suggests the germline mutation, and a developing country often means it presents late with advanced disease. Retinoblastoma and squint go together in the paediatric list: white pupillary reflex or squint.