From the Guidelines

Petrous apex cholesterol granuloma is a rare, benign lesion that occurs in the petrous apex of the temporal bone.

It is not directly mentioned in the provided evidence 1, but based on general medical knowledge, it is known to be a type of lesion that can cause symptoms due to its location and potential for expansion.
The evidence provided focuses on vestibular schwannoma and its diagnosis and treatment 1, which is a different condition, but it highlights the importance of imaging techniques like MRI in evaluating lesions in the skull base, including the petrous bone.

Symptoms of petrous apex cholesterol granuloma can include hearing loss, vertigo, and facial weakness, among others, depending on the size and exact location of the lesion.
Treatment options may involve surgical excision, with or without drainage, aimed at relieving symptoms and preventing further complications.
Medical management with corticosteroids, such as prednisone, may be used to reduce inflammation, although specific dosages and durations (e.g., 30-60 mg daily for 4-6 weeks) can vary based on clinical judgment and patient response.
In some cases, low-dose radiation therapy might be considered to control symptoms and prevent recurrence, though this is less common and would depend on the specific clinical scenario and patient factors.

From the Research

A petrous apex cholesterol granuloma is a benign inflammatory cystic lesion of the temporal bone, specifically located in the petrous apex 2, 3, 4, 5, 6.
It is a readily recognizable and treatable entity that can grow slowly as a mass lesion, producing symptoms such as hearing loss, tinnitus, vertigo, and facial twitching 2.
Cholesterol granuloma is distinct from cholesteatoma, another type of lesion that can occur in the petrous apex, and requires different treatment approaches 2, 6.

The diagnosis of petrous apex cholesterol granuloma is based on both CT and MRI scans, which can show a sharply and smoothly marginated expansile lesion in the petrous apex, isodense with brain and nonenhancing on CT 2, 3, 5.
CT scans can be classified into different types, such as Type A (preserved apex cellularity), Type B (erosion of the apex cellularity), and Type C (involvement of the noble structures bone boundaries) 3.
MRI scans can also be used to evaluate the lesion and its relationship with surrounding structures 5.

The treatment of petrous apex cholesterol granuloma typically involves drainage and permanent fistulization, which can be performed through different surgical approaches, such as the extradural middle fossa approach or the endoscopic endonasal approach 2, 3, 4, 6.
The choice of treatment approach depends on the size and location of the lesion, as well as the patient's symptoms and overall health status 3, 4.
In some cases, a "wait and scan" approach may be recommended for asymptomatic patients or those with small lesions 3.