Gender distribution and sidedness of middle fossa arachnoid cysts: a review of cases diagnosed with computed imaging.

According to earlier reports, arachnoid cysts seem to occur more frequently in males, and on the left side. The latter phenomenon could, however, be explained by a greater significance attributed to symptoms from the dominant hemisphere as a justification for invasive procedures in the pre-computed tomography era. The literature from the last third of the era of computed tomography is reviewed with respect to gender distribution and sidedness for middle fossa arachnoid cysts. Also included are a few cases of our own from the same period. It is evident from this survey of the literature, based on computed tomography studies, that there is a significant tendency for these cysts to occur in males, with a male/female ratio of nearly 3:1. This preponderance toward males could not be explained by the somewhat higher frequency of associated subdural hematomas that was found in male patients. The survey also showed that middle fossa arachnoid cysts occur or are detected significantly more frequently on the left side than on the right, with a ratio of 1.8:1.