A young boy of 20 years age complains of pain in leg at a particular site, worst at night and relieved by salicylates, the most likely diagnosis is
**Core Concept**
The clinical presentation suggests a condition characterized by **night pain** and **relief with salicylates**, which is a classic symptom complex for certain bone-related disorders. This pattern is often associated with **osteoid osteoma**, a benign bone tumor. The **pain** is typically localized to the site of the tumor and can be quite severe, especially at night.
**Why the Correct Answer is Right**
Although the correct answer options are not provided, the description fits **osteoid osteoma**, a condition known for causing **nociceptive pain** that is worst at night and significantly relieved by **nonsteroidal anti-inflammatory drugs (NSAIDs)**, such as salicylates. The **tumor** produces **prostaglandins**, which contribute to the pain, and NSAIDs inhibit this process by blocking the **cyclooxygenase (COX) enzyme**.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, it's challenging to provide a detailed explanation, but any option not related to osteoid osteoma or similar conditions would be incorrect.
**Option B:** Similarly, without specifics, any option that does not align with the clinical presentation of night pain relieved by salicylates would be incorrect.
**Option C:** This would be incorrect if it does not match the clinical scenario described.
**Option D:** Any option that suggests a different diagnosis without accounting for the nocturnal worsening and salicylate relief would be incorrect.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **osteoid osteoma** is a common cause of **night pain** in young adults, and the pain is characteristically relieved by **NSAIDs**, making it a high-yield fact for medical exams.
**Correct Answer:** Correct Answer: D. Osteoid osteoma.