**Core Concept**
Tuberous sclerosis is a genetic disorder characterized by the growth of non-cancerous tumors in various parts of the body, including the skin, brain, kidneys, and other organs. The condition is caused by mutations in the TSC1 or TSC2 genes, leading to the activation of the mTOR pathway and subsequent cellular proliferation.

**Why the Correct Answer is Right**
McCollon plaques are a type of skin lesion typically associated with dermatomyositis, an autoimmune disease that causes muscle weakness and skin inflammation. They are characterized by pink to purple, scaly patches on the skin, often on the elbows, knees, and knuckles. In contrast, tuberous sclerosis is characterized by distinct skin lesions such as shagreen patches, adenoma sebaceum, and depigmented nevi. These lesions are caused by the abnormal growth of skin cells due to the mTOR pathway activation.

**Why Each Wrong Option is Incorrect**
**Option A:** Shagreen patches are a classic skin lesion in tuberous sclerosis, characterized by a rough, leathery texture and often found on the lower back. They are caused by the abnormal growth of collagen fibers due to the mTOR pathway activation.
**Option B:** Adenoma sebaceum is another distinctive skin lesion in tuberous sclerosis, characterized by multiple facial angiofibromas (red to purple bumps) on the nose, cheeks, and chin. These lesions are also caused by the abnormal growth of skin cells due to the mTOR pathway activation.
**Option D:** Depigmented nevi are a type of skin lesion that can be seen in tuberous sclerosis, characterized by areas of skin where the pigment cells are absent. They are caused by the abnormal growth of skin cells due to the mTOR pathway activation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that tuberous sclerosis is a genetic disorder with a high penetrance, meaning that individuals with the disease-causing mutations will almost certainly develop symptoms. However, the age of onset and severity of symptoms can vary significantly between individuals.

**✓ Correct Answer: C. McCollon Plaques**