**Core Concept**
Tietze syndrome is a self-limiting inflammatory condition characterized by the swelling of the cartilaginous structures of the anterior chest wall. This condition often presents with pain and tenderness in the affected area, typically involving the costochondral joints.

**Why the Correct Answer is Right**
Tietze syndrome is caused by inflammation of the costochondral junctions, which are the points where the ribs join the costal cartilages. This inflammation leads to swelling and pain in the affected area. The condition is often associated with a viral upper respiratory tract infection, and the inflammation is thought to be mediated by the release of pro-inflammatory cytokines and the activation of immune cells in the affected tissues.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to Tietze syndrome, which specifically involves the costochondral joints and not the sternoclavicular joint.

**Option B:** This option is incorrect because Tietze syndrome does not involve the pleura, which is a thin layer of tissue that lines the lungs and chest cavity.

**Option C:** This option is incorrect because Tietze syndrome is not a condition that affects the pericardium, which is a sac that surrounds the heart.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of Tietze syndrome is the presence of localized tenderness and swelling in the affected area, which can be difficult to distinguish from other conditions such as costochondritis or pleurisy.

**Correct Answer:** C. costochondral joints.