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 region. These symptoms are often present since infancy and recognised after the development of a subdural haematoma or complaints. Two cases are presented, one with exophthalmos since infancy due to a displacement of the lateral orbital bones, compressing the orbital contents, another with exophthalmos that developed at the age of 46 showing a rostral displacement of the middle cranial fossa also. Exophthalmos may be the only sign of a middle fossa cyst. Its cause is most likely orbital bone displacement and the subsequent protrusion of the orbital contents.