Spontaneous delayed CSF rhinorrhea associated with encephalocele following surgical resection of a giant frontoparietal meningioma, an extremely rare entity and overlook of English literature

Spontaneous cerebrospinal fluid (CSF) rhinorrhea without a history of head trauma is rare. The authors describe a scarce case of spontaneous, nontraumatic, delayed CSF rhinorrhea due to ethmoidal encephalocele associated with frontoparietal giant meningioma. A 49-year-old male complained of a slowly growing skull mass lasting 10 years since a blunt head trauma and progressive hemiparesis 3 months ago and was referred to our center. There was a heterogeneous extra-axial mass (77×77×70 mm) with calcified components at his right frontal lobe, demonstrating notable adjacent parenchymal edema and a midline shift to the left. There was a sizeable extra-axial mass (113×95×80 mm) in his right front-temporoparietal lobe associated with adjacent invasion to calvarium leading to the lytic and sclerotic appearance of the calvarial bone showing intense heterogeneous contrast enhancement and an adjacent enhancing dural tail. A considerable mass effect on the adjacent frontotemporal cortex is evident, with mild parenchymal edema leading to a notable midline shift to the left, right uncal herniation, and left ventriculomegaly. On postoperation day 5, the patient developed a recurrent CSF leak exacerbated by hydrocephalus. He was rescheduled to undergo endoscopic endonasal surgery and dural repair on postoperative day 7. The postoperative course was uneventful. Frontoparietal lobe encephaloceles represent the least common cause of spontaneous CSF rhinorrhea. Early diagnosis and surgical management remain crucial to minimize the subsequent complications. The ventricular anatomy and CSF fluid dynamics alteration following tumor surgical resection seem to contribute to an environment by which a herniated ethmoidal encephalocele developed a delayed nontraumatic CSF leak.