Intracranial grade I meningiomas: Confrontation between histological examination and magnetic resonance imaging.

Introduction: Meningiomas are tumors derived from arachnoid cells. More than 90% of cases have a benign clinical course and are classified as grade I according to the World Health Organization. A confrontation between radiologic findings and pathological examination is necessary to predict the grading of meningiomas.
Objectives: To study the radiological presentation by magnetic resonance imaging (MRI) and pathological features of intracranial meningiomas grade I.
Methods: This was a retrospective descriptive study of a series of 35 cases of grade I meningiomas. A review of MRI images was performed in this study.
Results: Our series consisted of 25 female and 10 male patients with a mean age of 49.2 years.The tumor was localized at the base of the skull in 20 cases (57.14%). The average size was 49 mm. At MRI, all meningiomas were solid showing enhancement after injection of contrast agent. This enhancement was homogeneous in 21 cases and heterogeneous in 14 cases. The edema was broad and extended in 15 cases, reduced in 8 cases and absent in 12 cases. The mean minimum apparent diffusion coefficient was 0.77 and the mean maximum average diffusion coefficient was 0,8. On histological examination, the meningioma was of meningotheliomatous type in 23 cases (65.7%), fibroblastic in 8 cases (22.9%), transitional 3 cases (8.6%) and angiomatous in one case (2,8%).
Conclusion: Although the final diagnosis of meningioma is mainly based on pathological examination, comparison with imaging is also important to orient the pathologist.