## **Core Concept**
Osteosarcoma, also known as osteogenic sarcoma, is a type of bone cancer that primarily affects children and young adults. It is a malignant tumor that originates from the osteoid tissue in bones. The peak incidence of osteosarcoma occurs during the adolescent growth spurt.

## **Why the Correct Answer is Right**
The correct answer, **B. 10-20 years**, is right because osteosarcoma has a bimodal age distribution. The first peak occurs during adolescence, which corresponds to the period of rapid bone growth, making **10-20 years** a critical age range. This age group is particularly susceptible due to the high rate of bone turnover and growth during puberty.

## **Why Each Wrong Option is Incorrect**
- **Option A: 0-10 years** - While osteosarcoma can occur in children, the peak incidence is slightly higher in the adolescent age group.
- **Option C: 40-60 years** - This age group is not typically associated with the peak incidence of osteosarcoma, although it can occur in adults, especially in the context of secondary osteosarcoma related to pre-existing bone lesions or radiation exposure.
- **Option D: 60-80 years** - This age range is not characteristic of the primary peak incidence of osteosarcoma.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that osteosarcoma often presents with systemic symptoms such as weight loss, fever, and night pain, in addition to localized bone pain. Early recognition and biopsy are crucial for diagnosis. Osteosarcoma is also known to metastasize, most commonly to the lungs.

## **Correct Answer: B. 10-20 years**