The Galassi classification is used for the neuroradiological classification of Arachnoid cysts in the middle cranial fossa into three distinct types and was first described in 1982 by Galassi et al.[^1].
Classification
Galassi type | Criteria |
Galassi type I | Small and spindle-shaped. The cyst is located in the anterior portion of the temporal fossa. The Temporal pole is compressed posteriorly, without a significant mass effect. There is no displacement of the Ventricular system or the midline. |
Galassi type II | The lesion is medium-sized and triangular or quadrangular in shape. It occupies the anterior and middle portions of the temporal fossa and extends superiorly along the Sylvian fissure. As a result, the temporal lobe appears shortened. |
Galassi type III | The lesion is large and appears oval or round. It occupies almost the entire space in the temporal fossa and extends into the respective hemisphere, separating the Operculum from the Sylvian fissure. The temporal lobe appears atrophic, and the Frontal- and Parietal lobe are largely compressed. There is a clear mass effect with displacement of the ventricular system and the midline. |
