RARE-11INTRACRANIAL ATYPICAL RHABDOID MENINGIOMA LACKING MALIGNANT FEATURES: CASE REPORT AND LITERATURE REVIEW

Abstract

RARE-11. INTRACRANIAL ATYPICAL RHABDOID MENINGIOMA LACKING MALIGNANT FEATURES: CASE REPORT AND LITERATURE REVIEW Mansour Mathkour1,2, Juanita Garces2, Joshua Hanna1, and Marcus Ware1; Ochsner Clinic Foundatino, Jefferson, LA, USA; Tulane Medical Center, New Orleans, LA, USA INTRODUCTION: Meningiomas are the most common benign intracranial tumors. They present with a number of cytological variants, most of which have no prognostic or clinical significance. One exceedingly rare variant is a meningioma with rhabdoid features, accounting for 2-3% of all meningiomas. This variant is also derived from meningoepithelial cells, however it is classified as WHO grade III owing to rapid growth, invasion of brain tissue and frequent recurrence. We describe a meningioma with rhabdoid features classified as WHO grade II as a result of uncharacteristically reduced malignant potential on cytology. To our knowledge there are three prior reported cases, two of which are intracranial of WHO Grade II meningioma with rhabdoid features. CASE: A 56-year-old male presented with abulia and slowed speech for several days. Physical exam of the patient was normal. Magnetic resonance imaging (MRI) of the brain revealed a focal heterogeneously enhancing extra-axial lesion within the left perisylvian region with mass effect on the left lateral ventricle. The patientunderwent craniotomy for tumor resection.The histological examination revealed meningioma with extensive rhabdoid features (greater than 50%). Cytology showed eccentric nuclei with abundant globoid eosinophilic cytoplasm consistent with rhabdoid features, however mitotic activity was relatively low with only 4 mitoses per 10 HPF. The patient is presently 4-months post-operation with resolution of his presenting symptoms and without evidence of recurrence. CONCLUSION: Meningiomas with rhabdoid features are known to be highly malignant with high recurrence rates, yet the tumor described by these authors exhibits reduced mitotic activity uncharacteristic of this tumor type. Based on our follow-up, there is currently no recurrence. We present a case of a rhabdoid meningioma with less aggressive features consistent with WHO II. As such, low-grade rhabdoid meningiomas should be considered as an exceedingly rare etiology, with unknown diagnostic and prognostic significance. Neuro-Oncology 17:v201–v206, 2015. doi:10.1093/neuonc/nov232.11 Published by Oxford University Press on behalf of the Society for Neuro-Oncology 2015.