## Core Concept
Wickham's striae are a characteristic histopathological feature observed in certain skin conditions. They represent a specific pattern of hypergranulosis and parakeratosis seen in the epidermis. The key condition associated with Wickham's striae is lichen planus.

## Why the Correct Answer is Right
Wickham's striae are a hallmark of lichen planus, a chronic inflammatory condition that affects the skin, mucous membranes, and other areas. These striae are observed as fine, white or gray lines visible on the surface of the skin lesions, particularly after applying oil or on dermoscopic examination. Histologically, they correspond to the presence of a granular cell layer (hypergranulosis) and the retention of nuclei in the stratum corneum (parakeratosis) in a characteristic pattern. This feature is a key diagnostic criterion for lichen planus.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because Wickham's striae are not typically associated with this condition (no specific condition mentioned).
- **Option B:** Similarly, this option does not correctly correspond with Wickham's striae.
- **Option D:** This option is also incorrect as it does not relate to the characteristic finding of Wickham's striae.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that Wickham's striae are pathognomonic for lichen planus. Their presence, especially when observed under a dermatoscope, can significantly aid in the diagnosis of this condition. Lichen planus can affect various parts of the body, including the skin, oral mucosa, and nails, and Wickham's striae can be found in lesions from these areas.

## Correct Answer Line
**Correct Answer: C. Lichen planus**