An unusual cause of trochlear nerve palsy and brainstem compression

Abstract

Schwannoma originates from the Schwann cells at the Obersteiner-Redlich zone, which marks the junction of central and peripheral myelin of the cranial nerves. Most frequently affected are the vestibular, trigeminal, and facial nerves followed by the lower cranial nerves. Trochlear schwannoma in the absence of neurofibromatosis is a rare entity. The purpose of this report is to serve as a reminder to consider trochlear nerve schwannoma in the list of differential diagnosis of such tumors as the outcome is far better than the intraaxial tumor in that location.