A 2-year-old boy from rural Maharashtra is brought to the ophthalmology clinic by his mother with a complaint of white pupillary reflex (leukocoria) in the left eye noticed 3 weeks ago. The child has no pain, redness, or discharge. On examination, the left eye shows a white reflex with media haze. Dilated fundoscopy reveals a creamy-white intraocular mass arising from the retina with areas of calcification. The right eye appears normal. Ultrasound B-scan of the left eye confirms a highly echogenic mass with calcification. What is the most appropriate next step in management?

Explanation

## Diagnosis and Staging Context This is a unilateral retinoblastoma (RB) presenting with classic leukocoria in a young child. The presence of intraocular calcification on ultrasound is highly suggestive of retinoblastoma. ## Current Management Paradigm (Post-2010) **Key Point:** Modern retinoblastoma management has shifted from primary enucleation to chemotherapy-first approach (chemoreduction) followed by focal consolidation therapy, aiming to preserve vision and the globe whenever possible. **High-Yield:** The International Classification of Retinoblastoma (Murphree classification) and the International Intraocular Retinoblastoma Classification (IIRC) guide treatment decisions: - **Group A/B:** Chemotherapy + focal therapy (laser, cryotherapy, brachytherapy) - **Group C/D:** Chemotherapy + focal therapy or enucleation - **Group E:** Enucleation (phthisical eye, neovascular glaucoma, extensive disease) ## Management Algorithm ```mermaid flowchart TD A[Unilateral Retinoblastoma]:::outcome --> B{Classify by IIRC}:::decision B -->|Group A-D| C[Systemic Chemotherapy]:::action C --> D{Response to Chemo?}:::decision D -->|Good response| E[Focal Therapy: Laser/Cryo/Brachy]:::action D -->|Poor response| F[Enucleation]:::action B -->|Group E| G[Enucleation]:::action E --> H[Surveillance]:::action F --> I[Histopathology + Adjuvant Rx]:::action ``` ## Chemotherapy Agents (Chemoreduction) | Agent | Mechanism | Notes | |-------|-----------|-------| | Carboplatin | Alkylating agent | First-line; crosses blood-retinal barrier | | Etoposide | Topoisomerase II inhibitor | Often combined with carboplatin | | Vincristine | Microtubule inhibitor | Added for aggressive tumours | **Clinical Pearl:** Systemic chemotherapy (intravenous) achieves better intraocular drug penetration than topical or periocular routes and is the standard of care for intraocular RB. ## Why This Case Warrants Chemotherapy First 1. **Unilateral presentation** with no evidence of extraocular extension or metastasis 2. **Intraocular disease only** — amenable to chemoreduction 3. **Young age** — preservation of vision and globe is paramount 4. **Modern evidence** — chemotherapy-first approach has globe salvage rates of 70–90% in Groups A–D **Mnemonic: GLOBE SALVAGE** — **G**ood response to chemotherapy, **L**ess aggressive disease, **O**pportunity for focal therapy, **B**etter visual outcomes, **E** — Enucleation reserved for Group E or failed chemotherapy. ## Follow-up After Chemotherapy - Assess tumour response at 4–6 weeks post-chemotherapy - Apply focal therapy (laser photocoagulation or cryotherapy) to residual disease - Serial dilated fundoscopy and imaging every 4–6 weeks for first 2 years - Long-term surveillance for secondary malignancies (especially in hereditary cases) **Warning:** Enucleation is reserved for: - Group E disease (phthisical eye, neovascular glaucoma, massive tumour) - Failed chemotherapy with no response - Recurrent disease after focal therapy - Extraocular extension Immediate enucleation without chemotherapy is no longer standard of care for intraocular RB and deprives the child of a chance at globe and vision preservation. [cite:Boyd & Murphree, Retinoblastoma, in Ophthalmology 4e Ch 12]