En-coup-de sabre is a form of
**Core Concept**
En-coup-de-sabre is a rare condition characterized by a linear or curvilinear scar on the scalp, typically resulting from a direct blow to the scalp, usually in childhood. This condition is often associated with the development of a linear scleroderma "en coup de sabre" or a linear morphea, which is a form of localized scleroderma.
**Why the Correct Answer is Right**
The exact pathophysiology of en-coup-de-sabre is not fully understood, but it is believed to be an autoimmune response to a trauma. The condition is thought to result from the activation of fibroblasts, which leads to the deposition of collagen and the formation of a linear sclerotic plaque. This process is often accompanied by inflammation and the subsequent scarring of the skin.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because en-coup-de-sabre is not a form of alopecia. While the condition may result in hair loss, the primary characteristic is the formation of a linear or curvilinear scar.
**Option B:** This option is incorrect because en-coup-de-sabre is not a type of skin cancer. While the condition may result in the scarring of the skin, it is not a malignant process.
**Clinical Pearl / High-Yield Fact**
En-coup-de-sabre is often associated with a linear or curvilinear scar on the scalp, which may be accompanied by hair loss, skin thickening, and the development of a linear scleroderma "en coup de sabre" or a linear morphea. This condition is often seen in children and may be triggered by a direct blow to the scalp.
**Correct Answer:** D. Linear scleroderma "en coup de sabre"