As regards to intraocular retinoblastoma, which one of the following statements is false:
**Core Concept**
Retinoblastoma is a malignant tumor of the retina that affects children, and it can be inherited or sporadic. The disease is characterized by the presence of a mutation in the RB1 gene, which is a tumor suppressor gene. The inheritance pattern of retinoblastoma is crucial in determining the genetic counseling and risk assessment for the family members.
**Why the Correct Answer is Right**
Patients with sporadic retinoblastoma have a mutation in the RB1 gene in both copies, but this is a somatic mutation, which occurs in the body's cells and is not inherited from either parent. This means that they do not pass the mutated gene to their offspring. In contrast, individuals with hereditary retinoblastoma have a germline mutation in the RB1 gene, which is present in every cell of their body and can be passed on to their children. The correct answer, **B. Patients with sporadic retinoblastoma do not pass their genes to their offsprings**, highlights the importance of distinguishing between sporadic and hereditary cases of retinoblastoma.
**Why Each Wrong Option is Incorrect**
**Option A:** 94% of cases are sporadic. This statement is true, as the majority of retinoblastoma cases are sporadic, and only a small percentage are hereditary.
**Option C:** Calcification in the tumor can be detected on ultrasound scan. This statement is also true, as calcification is a characteristic feature of retinoblastoma, and ultrasound is a useful imaging modality for detecting it.
**Option D:** Reese-Ellsworth classification is useful in predicting visual prognosis following radiotherapy. This statement is true, as the Reese-Ellsworth classification system is a widely used method for staging retinoblastoma and predicting the visual prognosis following treatment.
**Clinical Pearl / High-Yield Fact**
Retinoblastoma is the most common intraocular malignancy in children, and early detection is crucial for improving the visual prognosis. The presence of calcification on imaging studies is an important diagnostic clue, and genetic counseling is essential for families with a history of hereditary retinoblastoma.
**✓ Correct Answer: B. Patients with sporadic retinoblastoma do not pass their genes to their offsprings**