Nontraumatic intradiploic arachnoid cyst of the sphenoid bone.

The intradiploic arachnoid cysts are rare radiological entities which are generally post-traumatic in nature and occur mostly in occipital region. We present a rare case of non-traumatic, asymptomatic intradiploic cyst of the greater wing of sphenoid in an elderly patient. The CT and MR imaging confirmed an intraosseous multiloculated cystic lesion which showed communication with the cerebrospinal fluid in anterior temporal fossa, through the small bony defects.