Extra-axial cavernous malformation of the cerebellopontine angle: illustrative case

BACKGROUND Extra-axial cavernous malformations (CMs) in the cerebellopontine angle (CPA) are rare, typically affect cranial nerves (CNs), and present significant therapeutic challenges. This report discusses the case of a patient with an extra-axial CM in the CPA involving the CN VII/VIII complex, alongside a systematic review of similar cases. OBSERVATIONS A literature search of the PubMed and Embase databases identified 216 articles, with 18 meeting the inclusion criteria, encompassing 21 cases (average age 42.6 years). The most common symptoms were hearing loss (86%), facial palsy (43%), and facial numbness (33%). After surgery, hearing improved in 26% of patients and facial palsy improved in 37%. Overall, 32% of patients experienced postoperative improvement. One death was reported. LESSONS These lesions can cause significant symptoms, often leading to unfavorable clinical outcomes despite surgical intervention. Gross-total resection with CN preservation is the goal, but more data with earlier intervention and longer follow-up are needed to refine treatment strategies. https://thejns.org/doi/10.3171/CASE24528