Presentation
Epilepsy.
Patient Data
Well-circumscribed broad-based right parietal parasagittal mass of extra-axial location. It shows an isosignal to the cortical grey matter on T1 and T2, high signal FLAIR with surrounding vasogenic edema. The postcontrast sequences show a vivid heterogeneous enhancement with a dural tail sign as well as mild erosion of the adjacent inner table of the skull. The mean ADC was almost equal to the normal brain parenchyma (810 x 10-6 mm2/s).
No calcification or hemorrhagic component is seen on the GE sequence. A rim of CSF signal around the mass is noted on coronal T2 sequence representing the "CSF cleft sign", indicating the extra-axial location of the mass. The adjacent of the superior sagittal sinus is patent well-demonstrated on postcontrast sequences and MRV.
Case Discussion
MRI features are most consistent with a right parietal meningioma probably atypical form.
Generally, it is difficult to distinguish benign meningioma (WHO grade I) from atypical meningioma (WHO grade II) based on general morphology. The most reliable feature is the presence of lower apparent diffusion coefficient values (reflecting higher cellularity).