Peritumoral edema resolves infrequently in surgically treated patients with intracranial meningioma- a retrospective study of 279 meningioma patients.

backgroundThe resolution of peritumoral brain edema (PTBE) following surgery for intracranial meningioma (IM) is poorly understood. We hypothesized that PTBE represents a more permanent rather than resolving parenchymal change. Therefore, our aim was to assess the frequency of PTBE resolution following gross total resection (GTR) of IM.

methodsIM patients who were operated on in the study hospital between 2000 and 2020, who had preoperative magnetic resonance imaging (MRI) showing PTBE and a follow-up MRI performed at least one year after surgery, were retrospectively identified. To minimize confounding by PTBE related to a postoperative residual tumor, only patients who had undergone GTR were included. PTBE was defined as hyperintensity on either pre- or postoperative fluid-attenuated inversion recovery (FLAIR) MRI sequences.

resultsA total of 279 adult meningioma patients were retrospectively identified. Of these, 208 (74.6%) were graded as World Health Organization grade 1 and 71 (25.4%) as grade 2. Of the 279 patients who had the first postoperative follow-up MRI at one year or later, PTBE changes persisted in 270 (96.8%) patients. However, over 90% resolution in PTBE volume was observed in 102 (35.8%) patients during the median MRI follow-up of 5.0 years (2.3-6.5). Higher edema index (p <.001) and temporal PTBE location (p =.018) were associated with higher resolution percentage of preoperative PTBE.

conclusionPersisting PTBE is a common finding following GTR of IMs. While complete resolution of PTBE is rare, considerable resolution is often seen. The nature and exact cause of these persisting parenchymal changes are unclear, but they likely represent gliosis.