Correlation of Surgical Outcomes of Petroclival Meningiomas with Clinicoradiologic Parameters and Molecular and Chromosomal Alterations.

OBJECTIVE:To identify clinical, radiologic, intraoperative, histopathologic, and molecular factors that might affect the surgical outcome of petroclival meningiomas. METHODS:Medical records of 53 cases of petroclival meningiomas operated from 2003 to 2021 were reviewed for clinicoradiologic and molecular factors that were correlated with extent of resection. RESULTS:Modified Dolenc-Kawase anterior transpetrous rhomboid (44, 83.0%) was the most commonly used approach, followed by retrosigmoid (2, 3.8%) and combined (7, 13.2%) approaches. Hypointense tumors on T2-weighted magnetic resonance imaging (odds ratio [OR] 5.85; 95% confidence interval [CI] 1.70-20.41) and presence of brainstem edema (OR 4.53; 95% CI 1.36-15.12) were found to be significant factors increasing the likelihood of subtotal resection (STR; P = 0.004 and P = 0.011, respectively). In the presence of both tumor T2 hypointensity and brainstem edema, there was a significant increase in the likelihood of STR (P = 0.001; OR 25; 95% CI 3.52-177.48). Of the 16 cases for which molecular analysis was performed, no specimen was found to have pTERT, AKT-1 E17K, and SMO L412F and W535L mutations. All (100%) the patients harboring H3K27me3 loss and/or hemizygous CDKN2A deletion had cavernous sinus extension compared with 62.5% of patients without H3K27me3 loss and 72.7% with hemizygous CDKN2A retention. Similarly, hemizygous CDKN2A deletion and H3K27me3 loss were associated with an increase in the rate of brainstem edema from 27.3% to 60% and 25% to 50%, respectively. CONCLUSIONS:T2 hypointense tumor and brainstem edema on preoperative imaging are significant predictors of STR. H3K27me3 loss and hemizygous CDKN2A deletion may be associated with cavernous sinus extension, suggesting their role in tumor spread.