Akademik Veri Yönetim Sistemi
World Neurosurgery, cilt.135, ss.112, 2020 (SCI-Expanded)
© 2019 Elsevier Inc.Trochlear schwannoma in the absence of neurofibromatosis is a rare entity.1 These schwannomas originate usually from the intradural cisternal part of the nerve and expand in the ambient and interpeduncular cisterns as well as inferiorly in the upper part of the cerebellopontine cistern.2 This case involves a rare pontomesencephalic lesion removed successfully via the simple retrosigmoid suboccipital route (Video 1). A 49-year-old woman presented to our institute with decreased sensation on the left side of her body for 2 months. Neurologic examination revealed left hemihypoesthesia. Cranial magnetic resonance imaging revealed a lobulated, heterogeneously enhanced cystic tumor within the right ambient cistern compressing the adjacent midbrain and extending to the cerebellopontine angle. After obtaining consent for surgery, the patient underwent a right suboccipital retrosigmoid approach for exploration and resection of the lesion. During the operation, it was determined that the tumor originated from the trochlear nerve. Nerve-sparing surgery was performed with intraoperative neuromonitoring including cranial nerve V, VII, X, XI, and XII electromyography and muscle motor evoked potentials. Gross total resection of the tumor was achieved. In the early postoperative period, the patient's eye movements were normal in all directions. The patient did not have any visual problems and experienced improvement in hemihypoesthesia. She was discharged on the third postoperative day. Pathologic examination confirmed diagnosis of schwannoma. At 2 months after surgery, the patient's eye movements were intact, and trochlear nerve palsy did not occur. The patient gave written informed consent for surgery and publication of this case report.