Meningiomas: the decision not to operate.

In a consecutive series of 100 patients diagnosed with meningiomas, we advised 12 patients not to have surgery, and followed them from 3.3 to 12.8 years (mean, 8.8 years). The two determinants of this decision were either absence of related neurologic symptoms or signs and concern about high operative risk of neurologic impairment. Serial imaging studies showed meningioma growth in only one of the 12 unoperated patients and only one had convincing progression of neurologic impairment.