A rare combination of a meningioma and an ethmoidal meningoencephalocele with osteo-dural defect: Diagnostic and therapeutic challenges

Background: Meningiomas are common, benign intracranial tumors, while meningoencephaloceles are rare congenital or acquired anomalies commonly associated with a dural defect. Their association is exceptional and poses a diagnostic and therapeutic challenge. Case Description: We present a case of a 35-year-old female patient who presented with chronic headaches, blindness, and decreased hearing for 2 years. An Ear-Nose-Throat (ENT) examination revealed a right endonasal mass on nasofibroscopy. Brain magnetic resonance imaging showed a large right temporo-parietal lesion with features suggestive of a meningioma, and a right endonasal lesion extending into the frontal lobe through a bone defect in the ethmoid bone, suggesting a meningoencephalocele. The meningioma was surgically excised (Simpson II), and histo-pathology confirmed a World Health Organization grade I meningothelial meningioma. Three months after surgery, the patient presented with right rhino-liquorrhea, and a decision to endoscopically treat the meningo-encephalocele was made, as well as repair the dural defect in ENT. The postoperative period was marked by failure of the dural closure, evidenced by the appearance of a compressive pneumocephalus and Pseudomonas aeruginosa meningitis. A transcranial approach allowed for effective repair with immediate cessation of the rhinoliquorrhea. Resorption of the pneumocephalus was observed 1 month after surgery by a follow-up computed tomography scan. Conclusion: The association of a meningioma with a meningoencephalocele is extremely rare. The persistence of a dural defect exposes the patient to serious infectious complications. This case illustrates the complexity of managing such a combination and highlights the importance of early diagnosis, rigorous follow-up, and effective repair of any dural defect.