Intrasphenoidal encephalocele (CT cisternography)

Case contributed by Dalia Ibrahim
Diagnosis certain


Right sided CSF rhinorrhea.

Patient Data

Age: 45 years
Gender: Male

A small (about 3mm) bony defect is observed in the superior wall of the pneumatized lateral recess of the sphenoid sinus on the right side (lateral to the foramen rotundum). CSF fluid and anteromedial temporal lobe are seen herniating through the bony defect. CSF fluid tracks into the right side of the sphenoid sinus and the right ethmoidal air cells.

Empty sella is noted.

Case Discussion

Intrasphenoidal encephaloceles represent encephaloceles which extend into the sphenoid sinus yet confined by its floor.  

Contributing factors include arachnoid pits/weaknesses in the skull base and intracranial hypertension 

  • CSF pressures and the hydrostatic pulsative forces may lead to the development of pit holes on the middle fossa at the sites of arachnoid villi with herniation of dura/arachnoid or brain tissue 
  • If those defects are located over pneumatized lateral extension of the sphenoid sinus, encephalocele can develop and lead to CSF leakage into the sinus. 

Patients present with spontaneous cerebral spinal fluid CSF rhinorrhea.

CT cisternography demonstrate sphenoid sinus pneumatization, and a defect in the superior wall of the left lateral recess of the sphenoid sinus and anteromedial temporal lobe herniating through the bony defect.

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