Cystic schwannoma of the sphenoid sinus and skull base.

Skull base and intracranial cystic schwannomas are rare tumors. To our knowledge, a cystic schwannoma involving the sphenoid sinus has not been previously reported. The location and fluid-filled nature of the lesion resulted in an erroneous preliminary diagnosis of a destructive sphenoid sinus mucocele. Endoscopic biopsy and decompression established the correct diagnosis and reversed a progressive visual loss until definitive surgical removal of the lesion was accomplished. Diagnostic evaluation, histologic findings and management strategies are discussed.