## Core Concept
**Le Facies sympathique**, also known as the "sympathetic face," refers to a clinical sign associated with a specific appearance of a patient's face that indicates sympathetic nervous system stimulation or activation. This can be seen in various conditions, including pheochromocytoma, anxiety, or other states of sympathetic hyperactivity.

## Why the Correct Answer is Right
The correct answer, . **Horner's syndrome** is characterized by ptosis, miosis, and anhidrosis on the affected side of the face. However, Le Facies sympathique typically presents with the opposite signs: mydriasis (pupil dilation), and often, facial flushing and sweating due to increased sympathetic activity.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because it does not accurately describe Le Facies sympathique.
* **Option B:** This option is incorrect because, although it might relate to some symptoms seen in sympathetic hyperactivity, it does not specifically describe Le Facies sympathique.
* **Option C:** **Pheochromocytoma** can cause episodes of sympathetic hyperactivity, which might manifest as Le Facies sympathique, making it a condition associated with the described facial appearance.
* **Option D:** This option is incorrect because it does not relate to Le Facies sympathique.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that Le Facies sympathique can be observed in patients with **pheochromocytoma**, a tumor of the adrenal gland that leads to excessive secretion of catecholamines (like adrenaline and noradrenaline), causing episodes of hypertension, tachycardia, sweating, and the characteristic facial appearance.

## Correct Answer: C. Pheochromocytoma