ARACHNOID CYSTS OF THE MIDDLE CRANIAL FOSSA WITH EXOPHTHALMOS

Arachnoid cysts of the middle cranial fossa may cause local bulging of the skull with exophthalmos when located in the anterior temporal reg ion. These symptoms are often present since infancy and recognised aft er the development of a subdural haematoma or complaints. Two cases ar e presented, one with exophthalmos since infancy due to a displacement of the lateral orbital bones, compressing the orbital contents, anoth er with exophthalmos that developed at the age of 46 showing a rostral displacement of the middle cranial fossa also. Exophthalmos may be th e only sign of a middle fossa cyst. Its cause is most likely orbital b one displacement and the subsequent protrusion of the orbital contents .