A one year old child having leucocoria was detected to be having a unilateral, large retinoblastoma filling half the globe. Which of the following is the therapy of choice?
**Core Concept**
Leucocoria in a one-year-old child, associated with a unilateral, large retinoblastoma filling half the globe, suggests a high-risk retinoblastoma requiring prompt and aggressive management. The goal of therapy is to preserve life, maintain vision, and minimize treatment-related complications.
**Why the Correct Answer is Right**
The therapy of choice for large unilateral retinoblastoma is enucleation, which involves surgical removal of the affected eye. This approach is preferred because it provides histopathological diagnosis, removes the tumor, and reduces the risk of local recurrence. Enucleation also allows for the assessment of the tumor's histopathological features, which is crucial for determining the risk of metastasis and planning further treatment.
**Why Each Wrong Option is Incorrect**
* **Option A:** Chemotherapy and focal therapy (e.g., laser photocoagulation, cryotherapy) may be used in smaller, more localized retinoblastomas or as an adjunct to enucleation, but they are not the primary treatment for a large unilateral tumor filling half the globe.
* **Option B:** Brachytherapy involves the placement of radioactive material directly into or near the tumor. While it may be used in certain cases of retinoblastoma, it is not the therapy of choice for a large unilateral tumor.
* **Option D:** External beam radiation therapy (EBRT) may be used in some cases of retinoblastoma, especially in patients with more advanced disease. However, it is not typically the first-line treatment for a large unilateral tumor and carries a risk of secondary malignancies.
**Clinical Pearl / High-Yield Fact**
Retinoblastoma is the most common intraocular malignancy in children, and early detection is critical for improving outcomes. Leucocoria, or a white pupillary reflex, is a classic presentation of retinoblastoma, and prompt referral to a pediatric ophthalmologist or a pediatric oncologist is essential for diagnosis and treatment.
**Correct Answer:** C. Enucleation.