Bone tumour arising from metaphysis ?
**Core Concept**
The question is testing knowledge of the location of bone tumors within the bone. In orthopedic oncology, bone tumors can arise from different parts of the bone, including the epiphysis, metaphysis, and diaphysis.
**Why the Correct Answer is Right**
The correct answer is **osteosarcoma**, which is a type of malignant bone tumor that typically arises from the metaphysis of long bones. This is because the metaphysis is an area of rapid bone growth, and osteosarcoma cells take advantage of this environment to proliferate. Osteosarcoma cells produce abnormal bone matrix that resembles woven bone, which is a characteristic feature of this tumor.
**Why Each Wrong Option is Incorrect**
**Option A:** Osteochondroma is a benign bone tumor that typically arises from the metaphysis, but it is not malignant and does not produce abnormal bone matrix.
**Option B:** Ewing's sarcoma is a malignant bone tumor that can arise from the diaphysis or metaphysis, but it is more commonly associated with the diaphysis and produces a different type of abnormal bone matrix.
**Option C:** Chondrosarcoma is a malignant bone tumor that typically arises from the epiphysis, not the metaphysis, and produces abnormal cartilage matrix.
**Clinical Pearl / High-Yield Fact**
Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, and it often presents with pain and swelling in the affected limb. Early diagnosis and treatment are crucial for improving outcomes.
**Correct Answer: C. Ewing's sarcoma.**