A patient presents with pain in the thigh, relieved by aspirin. X-ray shows a radiolucent mass surrounded by sclerosis. Diagnosis is –
**Core Concept**
The patient's symptoms and radiographic findings suggest a diagnosis related to bone pathology, specifically a type of bone tumor or cyst.
**Why the Correct Answer is Right**
The patient's pain relief with aspirin, a nonsteroidal anti-inflammatory drug (NSAID), suggests an inflammatory component to the condition. The radiolucent mass surrounded by sclerosis on X-ray is characteristic of a bone cyst, such as an aneurysmal bone cyst (ABC). ABCs are typically benign, expansive lesions that can occur in any bone but are most common in the long bones of the extremities. They are often associated with a pathognomonic radiographic appearance of a "soap-bubble" or "honeycomb" appearance due to the presence of fluid-filled cavities within the lesion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the radiographic description provided. A non-ossifying fibroma (NOF) is a type of benign bone tumor, but it typically presents as a well-defined, radiolucent lesion with a surrounding zone of sclerosis, rather than a radiolucent mass surrounded by sclerosis.
**Option B:** This option is incorrect because it does not account for the patient's pain relief with aspirin. A giant cell tumor (GCT) is a type of benign bone tumor that can occur in the long bones of the extremities, but it typically presents as a lytic lesion with a characteristic "soap-bubble" appearance due to the presence of numerous giant cells.
**Option C:** This option is incorrect because it does not match the radiographic description provided. An osteoid osteoma is a type of benign bone tumor that typically presents as a small, well-defined radiolucent nidus surrounded by a zone of sclerosis, rather than a radiolucent mass surrounded by sclerosis.
**Option D:** This option is incorrect because it does not account for the patient's pain relief with aspirin. A bone abscess is a type of infectious process that can occur in the bone, but it typically presents with signs of infection such as fever, swelling, and redness, rather than pain relief with aspirin.
**Clinical Pearl / High-Yield Fact**
The "honeycomb" or "soap-bubble" appearance on X-ray is a classic radiographic feature of an aneurysmal bone cyst (ABC), and should raise suspicion for this diagnosis in patients presenting with a radiolucent mass surrounded by sclerosis.
**Correct Answer: C. Osteoid osteoma.**