A 2-year-old boy from rural Maharashtra is brought to the pediatric ophthalmology clinic by his mother with a chief complaint of white pupillary reflex (leukocoria) in the left eye noticed 3 weeks ago. The child is otherwise healthy with no systemic complaints. On examination, the left eye shows a white reflex in the pupillary area, and intraocular pressure is 18 mmHg. Dilated fundoscopy reveals a large, white, friable intraocular mass with areas of calcification and vitreous seeding. The right eye appears normal. Ultrasound B-scan confirms a large echogenic mass with calcification. What is the most appropriate next step in management?

Explanation

## Clinical Context This case presents a unilateral retinoblastoma with advanced intraocular disease (large mass with vitreous seeding). The child is 2 years old, within the typical age range for diagnosis (median age 18 months). ## Management Algorithm for Retinoblastoma ```mermaid flowchart TD A[Retinoblastoma diagnosed]:::outcome --> B{Unilateral or Bilateral?}:::decision B -->|Unilateral| C{Intraocular only or Extraocular?}:::decision B -->|Bilateral| D[Systemic chemotherapy + focal therapy]:::action C -->|Intraocular, Group A-C| E[Systemic chemotherapy + focal therapy]:::action C -->|Intraocular, Group D-E| F{Salvageable eye?}:::decision C -->|Extraocular/Metastatic| G[Systemic chemotherapy + radiation]:::action F -->|Yes| E F -->|No| H[Enucleation]:::action E --> I[Monitor for response]:::action I --> J{Complete regression?}:::decision J -->|Yes| K[Long-term surveillance]:::outcome J -->|No| H ``` ## Key Point: Chemoreduction Strategy **High-Yield:** Modern management of intraocular retinoblastoma (even Group D–E) prioritizes globe salvage through systemic chemotherapy (neoadjuvant) followed by focal consolidation therapy (laser photocoagulation, cryotherapy, or brachytherapy), rather than immediate enucleation. This approach preserves vision and orbital anatomy. ## Classification (International Classification of Retinoblastoma) | Group | Features | Prognosis | |-------|----------|----------| | A | Small tumor, no vitreous seeding | >95% globe salvage | | B | Larger tumor, minimal vitreous seeding | >90% globe salvage | | C | Moderate vitreous seeding | 70–90% globe salvage | | D | Extensive vitreous seeding, hazy view | 50–70% globe salvage | | E | Phthisical eye, neovascular glaucoma, massive tumor | <10% salvage; enucleation indicated | **Clinical Pearl:** Vitreous seeding (as in this case) does NOT automatically mandate enucleation; it is treatable with chemotherapy and focal therapy. Group E features (phthisis, neovascular glaucoma, inability to visualize posterior segment) are the true indications for primary enucleation. ## Treatment Sequence 1. **Systemic chemotherapy** (intravenous): carboplatin, etoposide, vincristine (CEV regimen) — 4–6 cycles over 3–4 months. This shrinks the tumor and reduces vitreous seeding. 2. **Focal consolidation therapy**: laser photocoagulation or cryotherapy applied after chemotherapy to ablate residual disease. 3. **Monitoring**: serial dilated fundoscopy and imaging (ultrasound/MRI) to assess response and detect recurrence. **Warning:** Enucleation is reserved for: - Group E disease (phthisical eye, secondary glaucoma, massive tumor with no light perception) - Failure to achieve regression after chemotherapy + focal therapy - Extraocular extension or orbital involvement - Metastatic disease at presentation ## Why This Case Warrants Chemoreduction Although this child has Group D disease (vitreous seeding), the eye is still salvageable: IOP is normal (18 mmHg), and the posterior segment is visible. Systemic chemotherapy followed by focal therapy offers a 50–70% chance of globe salvage and preserved vision, making it the standard of care. [cite:Boyd & Manzitti, Retinoblastoma, in Pediatric Ophthalmology & Strabismus, 5e]