In a child with retinoblastoma, which of the following is NOT a common finding in the X-ray: September 2012
**Core Concept**
Retinoblastoma is a malignant tumor of the retina, often presenting in children. X-rays may be used in the diagnostic workup to evaluate the extent of disease and identify calcifications within the tumor.
**Why the Correct Answer is Right**
The correct answer is based on the fact that retinoblastoma typically presents with calcifications within the tumor. These calcifications are a key feature of retinoblastoma and are often visible on X-rays. The tumor's rapid growth and high cell turnover lead to the deposition of calcium within the tumor cells, making it visible on X-rays.
**Why Each Wrong Option is Incorrect**
**Option A:** While retinal detachment can be a complication of retinoblastoma, it is not a common finding on X-ray. Retinal detachment would be better visualized on clinical examination or with imaging modalities like ultrasound or MRI.
**Option B:** The presence of a "sunset glow" appearance on X-ray is a common finding in cases of retinoblastoma, particularly in advanced cases where the tumor has calcified.
**Option C:** Optic nerve involvement is a common finding in advanced cases of retinoblastoma, and may be visible on X-ray as a widening or thickening of the optic nerve.
**Clinical Pearl / High-Yield Fact**
Retinoblastoma is the most common intraocular malignancy in children, and is often associated with a genetic mutation in the RB1 gene. The presence of calcifications within the tumor is a key feature of retinoblastoma and is often visible on X-rays.
**Correct Answer:** A.