INTRASELLAR ARACHNOID CYSTS - COMPUTED-TO MOGRAPHY AND MRI IN 2 CASES

We describe the computed tomographic and magnetic resonance imaging fi ndings in two cases of intrasellar arachnoid cysts. The diagnosis of i ntrasellar arachnoid cyst with suprasellar extension should be evoked in case of a cyst-like formation whose density and signal appear to be identical to those of the cerebrospinal fluid even if contrast uptake is evidenced in the cyst wall, Contrast uptake fan be related to comp ression of the pituitary stalk and normal pituitary displacement. Susp ected intrasellar arachnoid cyst modifies the surgical approach which must be made via a subfrontal route, We discuss the differential diagn osis with other intrasellar cystic formations such as necrosed tumors, absesses, Rathke pouch cysts, cystic craniopharyngiomas, epidermoid c ysts and parasite cysts.