A Systematic Review and Classification System for Cerebellopontine Angle Lipomas

Object: Cerebellopontine angle (CPA) lipomas are rare, benign, slow-growing masses. Resection is considered in symptomatic patients who are refractory to targeted medical therapy, but at this stage the lipoma has often reached considerable size and encompasses critical neurovascular structures. The objective of this study is to identify a type of lipoma that is most amenable to surgical resection.

Methods: The PubMed database was searched using relevant terms. Data on patient and lipoma characteristics was extracted and used to design a classification system. CPA lipomas were stratified by type with corresponding management and outcomes analyzed. Linear regression was used to test predictive variables against patient outcomes.

Results: One-hundred and seventeen patients with CPA lipomas were identified and 40 CPA lipomas were classified. The remaining CPA lipomas were deficient in data and not classified. No lipomas were classified as Type 1. Type 3 was most common (n = 16; 40%) and often surgically resected (n = 10; 62.5%). The majority of patients with Type 3 CPA lipomas undergoing surgical resection experienced symptom resolution or improvement (n = 6; 60%). Type 2 (n = 12; 30%) most often underwent serial surveillance (n = 5; 41.6%), with the majority of symptoms remaining unimproved (n = 2; 40%). Patients with Type 2 CPA lipomas treated with medical therapy (n = 3; 25%) often experienced symptom resolution (n = 2; 66.6%). Surgical resection of Type 2 CPA lipomas (n = 3; 25%) led to symptom resolution in all cases (n = 3; 100%) (p = 0.0499).

Conclusion: Type 2 CPA lipomas are smaller and would be deemed non-surgical in general practice, but our data suggests that these lipomas may benefit from early surgery. The advantages of early surgery are maximal resection, decreased surgical morbidity, and improved symptom relief. Further prospective, multicenter randomized studies are needed to validate these findings.