A 2-year-old boy is brought to the pediatric ophthalmology clinic by his mother with a chief complaint of white reflex in the left eye noticed 3 weeks ago. On examination, the child is otherwise healthy with normal developmental milestones. Visual acuity testing is difficult due to age, but the right eye appears to follow objects normally. Fundoscopy of the left eye reveals a white mass arising from the retina with areas of calcification and vitreous hemorrhage. The right eye appears normal on examination. Ultrasound B-scan of the left eye confirms a calcified intraocular mass. What is the most appropriate next step in management?

Explanation

## Clinical Presentation & Diagnosis This case presents a classic presentation of **unilateral retinoblastoma** in a 2-year-old child: - **Leukocoria (white reflex/amaurotic cat's eye)** — the most common presenting sign - **Intraocular calcification** on imaging — pathognomonic finding - **Vitreous hemorrhage** — indicates advanced intraocular disease - **Unilateral involvement** with normal contralateral eye **Key Point:** The presence of vitreous hemorrhage and calcification indicates Group D or E disease (International Classification of Retinoblastoma), which requires systemic therapy. ## Management Algorithm for Retinoblastoma ```mermaid flowchart TD A[Retinoblastoma diagnosed]:::outcome --> B{Unilateral or Bilateral?}:::decision B -->|Unilateral, Group A-C| C[Focal therapy ± chemotherapy]:::action B -->|Unilateral, Group D-E| D[Systemic chemotherapy first]:::action B -->|Bilateral| E[Systemic chemotherapy]:::action D --> F[Assess response]:::decision F -->|Good response| G[Focal therapy/EBRT]:::action F -->|Poor response| H[Enucleation]:::action C --> I[Preserve vision & eye]:::outcome G --> I H --> J[Prosthetic rehabilitation]:::outcome ``` ## Staging & Treatment Strategy | Feature | Group A–C | Group D | Group E | |---------|-----------|---------|----------| | **Prognosis** | Favorable | Intermediate | Unfavorable | | **First-line therapy** | Focal ± chemotherapy | Systemic chemotherapy | Systemic chemotherapy ± enucleation | | **Globe salvage rate** | 90–100% | 50–70% | <10% | | **Vitreous involvement** | Absent/minimal | Present | Extensive | **High-Yield:** Modern treatment paradigm prioritizes **globe salvage** through **neoadjuvant systemic chemotherapy** (intravenous or intra-arterial) followed by consolidation with focal therapy (laser, cryotherapy, plaque brachytherapy) or external beam radiotherapy (EBRT). Enucleation is reserved for eyes that fail to respond to chemotherapy or have secondary glaucoma/pain. **Clinical Pearl:** Intra-arterial chemotherapy (IAC) has become increasingly popular for advanced unilateral disease as it delivers high drug concentration directly to the eye while minimizing systemic toxicity. ## Why Systemic Chemotherapy First? 1. **Reduces tumor burden** and vitreous seeding 2. **Allows assessment of chemosensitivity** before definitive therapy 3. **Preserves vision** if eye salvage is possible 4. **Treats micrometastatic disease** if present 5. **Delays or avoids enucleation** in many cases **Key Point:** Immediate enucleation is no longer standard of care for newly diagnosed retinoblastoma; it is reserved for eyes that fail chemotherapy or develop complications like secondary glaucoma or phthisis. [cite:Boyd & Murphree, Pediatric Ophthalmology & Strabismus, Ch 11]