**Core Concept**
CSF otorrhea is a condition characterized by the leakage of cerebrospinal fluid (CSF) through the ear, resulting in a communication between the subarachnoid space and the middle ear or mastoid air cells. This condition often arises due to a defect in the temporal bone, which separates the cranial cavity from the external auditory canal.

**Why the Correct Answer is Right**
The most common cause of CSF otorrhea is a traumatic injury to the temporal bone, leading to a fracture that compromises the integrity of the bony labyrinth. This fracture can result in a direct communication between the subarachnoid space and the middle ear or mastoid air cells, allowing CSF to leak through the ear. The leakage can be unilateral or bilateral and may be accompanied by a conductive hearing loss.

**Why Each Wrong Option is Incorrect**
* **Option A:** While a congenital condition like a dehiscence or a malformation of the temporal bone may contribute to CSF otorrhea, it is not the most common cause.
* **Option B:** Infection, such as otitis media, can lead to complications like mastoiditis or petrous apicitis, but it is not a direct cause of CSF otorrhea.
* **Option C:** Tumors or neoplastic processes can cause CSF otorrhea by invading the temporal bone, but this is a less common cause compared to traumatic injury.

**Clinical Pearl / High-Yield Fact**
In cases of CSF otorrhea, it is essential to investigate for a possible temporal bone fracture, especially in patients with a history of trauma. A high index of suspicion and a thorough clinical examination, including audiometry and imaging studies, are crucial for making an accurate diagnosis.

**Correct Answer: C. Traumatic injury to the temporal bone.**