[A case of intrasellar arachnoid cyst].

Intrasellar arachnoid cyst is very rare. We report a case of intrasellar arachnoid cyst and review 15 cases which were previously reported. A 58-year-old male was admitted for evaluation of visual disturbance on April 24, 1981. Neurological examination revealed bilateral decreased visual acuity, optic atrophy and bitemporal hemianopsia. X-ray film of the skull showed a balloon-shaped sella turcica with thinning of the cortex of the sella floor. Axial and coronal CT scan showed a cystic lesion with water-density occupying the intrasellar and suprasellar region. After administration of contrast medium, no enhancement was noted. Bilateral carotid angiographies demonstrated that the carotid siphons were stretched and displaced laterally, the A1 portions of the anterior cerebral arteries were raised. Pneumoencephalography revealed the upward displacement of the floor of the third ventricle indicating the presence of the suprasellar mass. On May 7, 1981, the sella turcica was reached via the transsphenoidal rhinoseptal approach. A cyst with a white colored thin wall which contained water-like fluid was encountered, and a biopsy was taken of the cyst wall. The roof of the cyst pulsated downward and ruptured spontaneously. Cerebrospinal fluid flowed out. The cavity was filled with muscle and adipose tissue. Postoperative course was uneventful during the first few days and the visual disturbance improved. On the fourth postoperative day cerebrospinal fluid rhinorrhea occurred, but it subsided in nine days. The patient was discharged on June 26 with satisfactory improvement of visual field and visual acuity. Histological examination of the biopsied specimen revealed arachnoid membrane consisting of collagen fibers and scattered cells. Symptoms, signs and radiological findings of the intrasellar archnoid cyst are similar to that of various sellar lesions including pituitary adenoma, craniopharyngioma and the other space occupying mass in the sellar region. Intrasellar arachnoid cysts can be treated by a transsphenoidal approach as well as a subfrontal approach with craniotomy.(ABSTRACT TRUNCATED AT 250 WORDS)