A 2-year-old child is brought with leukocoria (white pupillary reflex) in the right eye. Examination under anaesthesia reveals a white intraocular mass with calcification. The most likely diagnosis and the gene involved are:

• A Persistent hyperplastic primary vitreous; FZD4 gene
• B Coats' disease; NDP gene on chromosome 11
• C Medulloepithelioma; WT1 gene
• D Retinoblastoma; RB1 gene on chromosome 13q14 ✓

Explanation

Retinoblastoma is the most common intraocular malignancy of childhood, presenting as leukocoria or white pupillary reflex. It arises from mutations in the RB1 tumor suppressor gene located on chromosome 13q14, following the two-hit hypothesis of Knudson. Calcification within the tumor on imaging (CT/ultrasound) is highly characteristic and helps distinguish it from other causes of leukocoria such as Coats' disease and persistent fetal vasculature.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.