## Core Concept
The description provided points towards a vascular malformation, specifically a **port-wine stain** or **nevus flammeus**, which is a type of birthmark. Port-wine stains are known to grow in proportion with the child and can be associated with various syndromes.

## Why the Correct Answer is Right
The correct answer, Sturge-Weber syndrome, is associated with **port-wine stains** typically located on the face, often in the distribution of the trigeminal nerve. This condition is characterized by a congenital vascular malformation affecting the skin, eyes, and central nervous system. The port-wine stain in Sturge-Weber syndrome usually appears at birth and grows with the child. The involvement of the forehead and temporal area, as described, is consistent with the presentation of Sturge-Weber syndrome.

## Why Each Wrong Option is Incorrect
- **Option A:** While certain conditions may present with skin lesions, there's no direct association with the described lesion type and growth pattern as specifically as with Sturge-Weber syndrome.
- **Option B:** Similarly, another condition might present with various symptoms, but it does not classically include a port-wine stain that grows with the child.
- **Option D:** This option might represent a different condition altogether, not typically associated with the type of skin lesion described.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that **port-wine stains** are often associated with **Sturge-Weber syndrome**, especially when located on the face in the trigeminal nerve distribution. These patients are at risk for **glaucoma** and **neurological abnormalities**, making early recognition crucial.

## Correct Answer Line
**Correct Answer: C. Sturge-Weber syndrome.**