- Etiology: heterogeneous group of tumors
- Imaging: anterior to fourth ventricle, can be tectal / ventral pons / dorsal pons / medulla, usually infiltrative, irregular enhancement (50%), can be exophytic and encase basilar artery, occasionally cystic
- DDX: granuloma, rhomboencephalitis, infarction, cryptic vascular malformation, demyelination, metastasis, radiation effect
- Complications:
- Treatment: non-resectable
- Clinical: cranial nerve palsy