A 2-year-old boy from rural Maharashtra is brought to the eye clinic by his mother with a chief complaint of white pupillary reflex (leukocoria) in the left eye for 3 months. On examination, the child is cooperative and visual acuity cannot be formally assessed. Dilated fundoscopy reveals a white intraocular mass arising from the retina with areas of calcification and vitreous haze. B-scan ultrasonography confirms a retinal mass with high internal reflectivity. The right eye appears normal on examination. There is no family history of retinoblastoma or other malignancies. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis and Staging **Key Point:** This child presents with unilateral retinoblastoma with advanced intraocular disease (vitreous seeding suggested by haze and calcification). The presence of a large retinal mass with calcification and vitreous involvement in a unilateral case with no light perception risk indicates a Group D or E eye by International Classification of Retinoblastoma (ICRB). ## Management Algorithm for Advanced Unilateral Retinoblastoma ```mermaid flowchart TD A[Retinoblastoma diagnosis confirmed]:::outcome --> B{Unilateral or Bilateral?}:::decision B -->|Unilateral| C{ICRB Group?}:::decision C -->|Group A-C| D[Globe-salvaging therapy]:::action C -->|Group D-E| E[Enucleation]:::action B -->|Bilateral| F[Chemoreduction + focal therapy]:::action E --> G[Histopathology + risk stratification]:::action G --> H{High-risk features?}:::decision H -->|Yes| I[Adjuvant chemotherapy]:::action H -->|No| J[Observation]:::action ``` **High-Yield:** For unilateral advanced retinoblastoma (ICRB Group D–E), enucleation is the standard of care because: - Globe salvage is unlikely to succeed with advanced disease - Enucleation provides complete histopathological assessment for prognostic risk factors (optic nerve invasion, choroidal invasion, anterior chamber involvement) - Histology guides adjuvant chemotherapy decisions - Prevents secondary glaucoma and chronic pain ## Pathological Risk Stratification Post-enucleation histopathology determines need for adjuvant chemotherapy: | Risk Factor | Impact | Requires Adjuvant Chemo? | |---|---|---| | Optic nerve invasion (beyond lamina cribrosa) | High risk | Yes | | Choroidal invasion (massive) | High risk | Yes | | Anterior chamber involvement | High risk | Yes | | Scleral invasion | Very high risk | Yes | | No high-risk features | Low risk | No | **Clinical Pearl:** Leukocoria (white pupil reflex) is the most common presenting sign of retinoblastoma, accounting for 60% of cases. Strabismus (20%) and eye pain/redness (less common) are other presentations. Early detection is critical—prognosis is excellent (>95% cure) in developed countries but poor in resource-limited settings due to late presentation. **Warning:** Do NOT attempt globe salvage in Group D–E unilateral disease. External beam radiation and systemic chemotherapy alone cannot control advanced intraocular disease and delay definitive treatment, increasing mortality risk. [cite:Boyd & Maudgil Retinoblastoma, Ocular Oncology textbook]