We reviewed the clinical, radiological, surgical, and histopathological features of patients with meningiomas to identify factors that can predict tumor recurrence after ''microscopic total removal,'' to improve preoperative surgical planning, and to help determine the need for close radiological observation at shorter intervals or the need for radiotherapy as an adjuvant treatment in the early postoperative period. Clinical data, magnetic resonance imaging studies, angiographic data, operative reports, and histopathological findings were examined retrospectively in 137 patients with a meningioma treated microsurgically and with no evidence of residual tumor on postoperative MR images. Based on univariate analysis, tumor size, a mushroom shape, proximity to major sinuses, edema, osteolysis, cortical penetration, signal intensity on T2-weighted MRIs, pial-cortical arterial supply, presence of a brain-tumor interface in surgery, Simpson's criteria, and histopathological classification were significant predictors for recurrence. However, age, gender, location of tumor, dural tail, calcification, signal intensity on T1-weighted images, and histopathologic subtypes in the benign group were not significant predictors. By Cox regression analysis the most important variables related to the time to recurrence were mushroom shape, osteolysis, dural tail, and proximity to major sinuses. Aggressive surgical therapy with wider dural removal should be considered in the presence of the preoperative predictors of a recurrence. Close radiological observation at shorter intervals or radiotherapy should be considered as adjuvant therapy in high-risk patients
