Giant skull base collision tumors in NF2-related schwannomatosis: longitudinal outcomes of planned selective resection.

OBJECTIVES

Giant skull base collision tumors in neurofibromatosis type 2-related schwannomatosis (NF2-SWN) pose a complex surgical challenge in young patients with lifelong tumor burden. Gross total resection is often impossible without severe neurological morbidity, and data on operative timing and durability are limited. We assessed long-term outcomes of planned, selective resection prioritizing neurological preservation.

METHODS

We queried a prospective institutional database for NF2-SWN patients undergoing surgery for giant (≥ 4.0 cm) intracranial skull base collision tumors (≥ 2 neoplasms forming one mass) from January 2009 to December 2025. Surgery targeted symptomatic or high-risk components, accepting residual disease. Outcomes included time to reoperation, overall survival, and functional status.

RESULTS

Thirteen patients underwent 31 skull base operations. Mean age at first surgery was 27 years (range 19-42), with mean tumor diameter 5.0 cm (range 4.0-7.7 cm). Most (69%) had prior surgery and/or radiotherapy. Gross total resection was never achieved. Over mean 9.4-year follow-up, Kaplan-Meier analysis demonstrated reoperation-free survival of 61.5% at 5 years (95% CI, 26.6-83.7%), with a median reoperation-free survival of 6.1 years. The mean interval between reoperations was 4.8 years (median, 3.9 years; IQR, 2.7-5.7; range, 0.8-14.6). Overall survival was 100% at 5 years and 88% at 10 years. At last follow-up, median Karnofsky Performance Status was 70.

CONCLUSION

Planned, selective resection of giant NF2-related skull base collision tumors yielded a median reoperation-free interval of 6.1 years and maintained functional independence in a young, heavily pretreated population, supporting its feasibility as a longitudinal management strategy.