MRI scans: (upper left) axial T2 weighted; (upper right) axial T1 weighted with gadolinium; (bottom left) coronal T1 weighted: (bottom right) coronal T1 weighted with gadolinium.Note the nodular mass in the region of the left pons that enhances with gadolinium. This is a schwannoma, a histologically benign tumor, that has arisen from cranial nerve V (the trigeminal nerve). Schwannomas are also characteristically seen arising from cranial nerve VIII, the vestibulo-cochlear nerve, where they are known as acoustic neuromas.