Expanded Endoscopic Transclival Approach for Resection of a Chordoid Meningioma without Dural Attachment (MWODA) Located in the Prepontine Cistern.

Background Meningiomas without dural attachment (MWODA) located in the posterior fossa are an unfrequent entity. They are usually located in the fourth ventricle, and their occurrence outside of this anatomic structure is an even more uncommon finding. Chordoid meningiomas are a rare subtype of meningioma, and they have been reported to account for 0.5%–1% of all meningiomas. Case description We report the unusual case of a 36-year-old female patient, with unremarkable past medical history, who presented at our institution complaining of acute binocular diplopia. Right cranial nerve VI paresis was observed on physical examination. Imaging studies revealed an intradural retroclival solid mass that enhanced homogeneously after contrast administration. Interestingly, no dural tail was present. Expanded endonasal endoscopic resection of her retroclival lesion was performed. We used a 4-hand technique with 0 and 30 degrees endoscopes, with intradural pituitary transposition. Gross total resection was achieved and the pathology report described findings consistent with chordoid meningioma. The patient is recurrence-free and in good condition at 1-year follow-up. Conclusions We performed a thorough review of the literature, and we found 10 reported cases describing extraventricular MWODA in the posterior fossa. To our knowledge, this is the first reported case of retroclival MWODA with pathologic findings consistent with chordoid meningioma.