Posterior fossa arachnoid cysts: two case reports.

2 cases of posterior fossa arachnoid cyst are discussed. In the first, it is likely that perinatal factors were responsible for the temporal lobe pathology and the formation of the cyst. Progressive dilatation of the temporal horn may have then been caused by obstruction from the cyst. In the second case, minor head trauma was a possible mechanism for the cyst production, although it seemed irrelevant to the mode of clinical presentation.