The choice of surgical approach for a petrous apex lesion depends on its relationship with the internal carotid artery, degree of medial expansion and pathology. The correct identification of patients who will benefit from this approach is necessary.

Two adult patients presented with a lesion in the left petrous apex. Computed tomography showed a homogeneous mass extending anteromedially, and abutting the internal carotid artery and the sphenoid sinus in both patients. Using magnetic resonance imaging, a third recurrence of cholesterol granuloma in case one and cholesteatoma in case two were diagnosed. Both patients underwent trans-sphenoid excision, as the sphenoid sinus was well pneumatised and the lesion was medial to the internal carotid artery.

Nasal endoscopic access to the petrous apex via the trans-sphenoid corridor should be preferred for benign lesions extending anteromedially in cases where lateral access is impeded by the internal carotid artery, the labyrinth and the facial nerve, and anterior trans-sphenoidal access offers a low-morbidity alternative.

This case report describes the endoscopic transsphenoidal management of a cholesterol granuloma situated in a technically challenging part of the petrous apex, and the associated peri- and post-operative complications that arose. The literature on diagnosis and management of petrous apex cholesterol granulomas is reviewed.

Surgical intervention was attempted on three occasions, each time via an endoscopic, transsphenoidal approach with image guidance. The procedure was abandoned on the first occasion as there was a significant risk to the carotid artery; only a small drainage ostium was created because of the proximity of the carotid artery. The second attempt, complicated by copious bleeding from the clival venous plexus, was arrested prematurely. Successful drainage was achieved at the third attempt, but recovery was complicated by tension pneumocephalus.

The transnasal route is less invasive than a lateral labyrinthine or cochlear approach, and spares cochlear and vestibular function. However, this approach is not without risk. It is important to consider the natural anatomical variance of vasculature when planning surgical intervention for a lesion situated in a technically challenging part of the petrous apex. Additional magnetic resonance venography is recommended to circumnavigate the venous plexus, thereby avoiding an unexpected breach.

We report a case of cholesterol granuloma of the petrous apex which was surgically treated via an endoscopic trans-sphenoidal approach.

Case report and review of the literature concerning cholesterol granulomas of the petrous apex and their management.

The lesion was approached endoscopically via a bilateral sphenoidotomy with removal of the vomer. A large cholesterol granuloma was evacuated and marsupialised. The patient made an uneventful recovery.

Trans-sphenoidal access to the petrous apex represents an alternative route for the drainage and ventilation of cholesterol granulomas. This approach is the technique of choice when the cholesterol granuloma abuts the posterior wall of the sphenoid sinus. The trans-sphenoid approach, unlike other lateral approaches to the petrous apex, spares cochlear and vestibular function and allows post-operative endoscopic follow up.