Spontaneous pseudomeningocele of sphenoid sinus or sphenoid mucocele?: A diagnosis dilemma

A pseudomeningocele is an abnormal collection of cerebrospinal fluid (CSF) that communicates with the CSF space around the brain or spinal cord. We describe a rare case of spontaneous non-traumatic pseudomeningocele in a 28 year-old gentleman who presented with delayed puberty associated with headache. Computed tomography revealed an expansile mass over bilateral sphenoid sinuses. Magnetic resonance imaging supported the diagnosis of sphenoid mucocele. A transnasal transphenoidal endoscopic sphenoidotomy was performed. Intraoperatively, despite an anatomical puncture through the sphenoid ostium, alarmingly, the opening leaked out CSF. A dehiscent was identified with a dural opening. This was repaired with multilayer technique. Clinical improvement was observed post-operatively. The case reported here is unusual as they presented on imaging as a fluid collection in sphenoid sinus simulating a mucocoele, but were filled with CSF and represent pseudomeningocele. Surgeons should be alert to the presence of pseudomeningocele as they can mimic a mucocele or nasal polyp.