Microcystic Meningiomas: MRI-Pathologic Correlation.

Abstract

Microcystic meningiomas (MM) are a distinctive, rare subtype of Grade Imeningiomaswith limitedradiological descriptions. We intend to identify unique imaging phenotypes and seek radiopathological correlations. Retrospective analysis ofhistopathologicallyproven MM was undertaken. Clinicodemographic profiles, imaging, and histopathological characteristics were recorded. Spearman rank correlations among radiological and pathological attributes were performed. Twenty-eight cases wereanalyzed(mean age = 45.5years;M:F= 1:1.54; mean volume = 50.1mL; supratentorial n = 27). Most lesions were markedly T2 hyperintense (higher than peritumoral brain edema-a unique finding) (89.3%) and showed invariable diffusion restriction, severe peritumoral brain edema (edema index >2 in 64.3%), a "storiform" pattern onT2-weighted images (T2WI) (75%), reticular pattern on postcontrastT1 (78.6%)/diffusion-weighted images (DWI) (65.4%),hyperperfusion, T1hypointensity(84.6%), and absence of blooming on susceptibility-weighted image (80.9%). Storiform/reticular morphology correlated with large cysts on histopathology (ρ = .56; P = .005753). Lesion dimension positively correlatedwith reticularmorphology on imaging(ρ = .59; P = .001173), higher flow voids(ρ = .65; P = .00027),and greater microcystic changes on histopathology(ρ = .51; P = .006778). Peritumoral brain edema was higher for lesions demonstrating greater angiomatous component (ρ = .46; P = .014451). We have elucidated varied neuroimaging features and highlighted pathological substrates of crucial imaging findings of MM.MMought tobe considered asan imaging possibilityin an extra-axial lesion with a marked hypodensity on noncontrast computed tomography, markedly T2-hyperintense/T1-hypointense signal, and a storiform/reticular pattern on T2W/GdT1w//DWI.