[Clinical observations of intracranial arachnoid cyst of the middle fossa (author's transl)].

: The patients are 15 year old and 13 year old males who complained of a headache, vomiting and general malaise. The plain skull films showed thinning and bulging of the left temporal squama, forwards enlargement of the middle fossa and the elevation of the lesser wing of the sphenoid. The left carotid arteriography indicated significant elevation of the middle cerebral artery and the opercular portion of the middle cerebral artery was absent. Left frontotemporoparietal craniotomy was performed, and the large cyst as the space taking mass lesion of the middle fossa was noted. The cyst contained xanthochromic fluid and its wall probably consisted of arachnoid membrane. In both cases the cyst occupied anterior 6 cm of the left middle fossa and no brain tissue was noted between the cyst and the anterior part of the middle cranial fossa. Histologically, the membrane of the cyst was arachnoid. Their recognition and management are discussed.