Hemorrhagic schwannoma of the trochlear nerve: Case report and a review of the literature

• Published in: Frontiers in oncology 2023-01, Vol.12, p.1097155
• Main Authors: Lei, Jin, Li, Yu, Wan, Xueyan, Wang, Junwen, You, Chao, Zhao, Kai, Niu, Hongquan
• Format: Article
• Language: English
• Subjects: intracranial schwannoma; intratumoral hemorrhage; neurosurgical oncology; Oncology; subtemporal approach; trochlear nerve
• ISSN: 2234-943X; 2234-943X
• DOI: 10.3389/fonc.2022.1097155

Schwannomas of the trochlear nerve with the absence of systemic neurofibromatosis are considerably uncommon, especially complicated by intra-tumoral hemorrhage. Due to the lack of typical clinical manifestations and imaging findings, a definite diagnosis of trochlear schwannomas before surgery is particularly difficult. We report the case of a 64-year-old female patient who presented with a unilaterally intermittent headache of 2-month duration and without a remarkable neurological deficit at admission. Imaging studies revealed a well-demarcated cystic-solid lesion with mixed signals beside the brainstem and suprasellar cisterna. The patient underwent a surgical operation with total resection of the tumor by a subtemporal surgical approach. The tumor was intraoperatively found to originate from the trochlear nerve and was pathologically confirmed as a hemorrhagic schwannoma with cystic degeneration. We describe this case in detail and conduct a concomitant survey of the literature, summarizing the clinical presentations, radiological features, surgical treatment, and the possible mechanisms of hemorrhage in relevance to trochlear nerve schwannoma.