IATROGENIC ARACHNOID CYST WITH DISTINCT CLINICAL PICTURE AS A RESULT OF BONE DEFECT IN THE FLOOR OF THE MIDDLE CRANIAL FOSSA - CASE-REPORT

OBJECTIVE AND IMPORTANCE: This kind of arachnoid cyst has not previous ly been described as a complication of a cranial base bone defect. Rec ognition of this rare complication may be delayed, because clinicians are unaware of its possibility. CLINICAL PRESENTATION: A 22-year-old m an presented with severe headache and increasing difficulty in breathi ng and swallowing. A physical examination revealed a pulsatile mass in the oral cavity, arising from the parapharyngeal area. A cystic mass that protruded into the oral cavity, through a dural and bony defect i n the left middle fossa, was detected on neuroimages. INTERVENTION: A left frontotemporal craniotomy was made, and the cyst was decompressed . Duraplasty was performed with lyophilized dura. The bone defect was managed with a calvarial free bone graft and a pedicled myofacial flap . Serial neuroimaging studies performed postoperatively showed that th e cyst had decreased in size. CONCLUSION: This report describes an unu sual complication of a cranial base bone defect. Although not all bone defects in the cranial base require reconstruction, management of the large bone defect, particularly in the middle fossa, should preferabl y be accomplished with the help of a bone graft to support the dural g raft.