A patient presents with pain in the thigh, relieved by aspirin. X-ray shows a radiolucent mass surrounded by sclerosis. Diagnosis is:
**Core Concept**
Osteogenic sarcoma, also known as osteosarcoma, is a malignant bone tumor that can present with pain and radiographic abnormalities. The presence of a radiolucent mass surrounded by sclerosis on an X-ray is characteristic of this condition.
**Why the Correct Answer is Right**
The correct answer is a type of osteosarcoma. Osteosarcoma arises from primitive mesenchymal cells within the bone and can present with a mix of radiolucent and radiopaque areas on X-ray due to the production of bone matrix by the tumor cells. The sclerosis surrounding the tumor represents reactive bone formation in response to the tumor. The pain in the thigh can be relieved by aspirin, which is a nonsteroidal anti-inflammatory drug (NSAID) that reduces prostaglandin synthesis and thereby alleviates pain and inflammation.
**Why Each Wrong Option is Incorrect**
**Option A:** Ewing's sarcoma is another type of malignant bone tumor, but it typically presents with a lytic lesion and a "moth-eaten" appearance on X-ray, rather than a radiolucent mass surrounded by sclerosis.
**Option B:** Fibrous dysplasia is a benign bone lesion that can present with a radiolucent area, but it does not typically have a sclerotic border.
**Option C:** Giant cell tumor is a benign bone lesion that can present with a lytic lesion, but it is more commonly found in the epiphyses of long bones and does not typically have a sclerotic border.
**Clinical Pearl / High-Yield Fact**
Osteosarcoma is the most common primary malignant bone tumor in children and young adults, and it often presents with pain and a palpable mass.
**Correct Answer:** C.