Petrous apex lesions.

OBJECTIVE

The accurate diagnosis of different petrous apex lesions is increasingly common as a result of modern imaging techniques, combining computed tomography and magnetic resonance imaging. The clinical features, diagnostic evaluation, imaging, and treatment outcomes of patients with petrous apex lesions are reviewed.

STUDY DESIGN

Retrospective case review.

SETTING

Private practice tertiary otologic referral center.

PATIENTS

Sixty-six patients treated at the House Ear Clinic in the last 2 decades for a lesion of the petrous apex. Lesions included cholesterol granuloma, cholesteatoma, and chondrosarcoma, among others. Mean follow-up time was 27 months and ranged from 1 month to 10 years.

INTERVENTION(S): Cholesterol granulomas were treated with drainage procedures, solid tumors were surgically removed using primarily the middle fossa or infratemporal fossa approaches.

RESULTS

The most common presenting symptoms were hearing loss, dizziness, headaches, and tinnitus. Decreased cranial nerve V function was present in 22%. The most common cystic lesion was cholesterol granuloma, which constituted 60% of all lesions in the study, followed by cholesteatoma (9%). Chondrosarcomas were the most common solid lesion (6% of all lesions). Asymmetric pneumatization and retained secretions give radiographic findings commonly overdiagnosed as lesions of the petrous apex.

CONCLUSIONS

Lesions of the petrous apex can be diagnosed accurately by CT and MRI and can be divided into cystic and solid lesions. Cholesterol granulomas are by far the most common lesion found in this site and can be drained with minimal morbidity via the infracochlear approach. Solid tumors may require extensive exposure and a combined skull base approach for complete removal.