A schwannoma at the lower cerebellopontine angle mimicking a brainstem glioma on neuroimaging: case report

This study reports the case of a schwannoma in the inferior cerebellopontine angle (CPA) that mimicked a brainstem glioma in imaging. The patient was a 35-year old male, who presented in February 2023 with dizziness that had persisted for six months and exacerbated on moving the neck. Imaging examinations, specifically cranial magnetic resonance imaging (MRI), revealed a mass in the left brainstem and cerebellar region, measuring approximately 3.7 × 2.6 × 3.8 cm. The mass was irregular in shape, showing slightly long T1 and mixed T2 signals. It locally compressed the fourth ventricle, and after contrast-enhanced scanning, significant heterogeneous enhancement was observed. Magnetic resonance spectroscopy (MRS) indicated that the peak heights of N-acetylaspartate (NAA) and choline complex in the lesion were approximately 0.049 and 0.524, respectively. Due to the extremely similar imaging features to those of a brainstem glioma, it was initially misdiagnosed as glioma. Total surgical resection was performed, and post-operative pathology confirmed it to be a schwannoma. The patient recovered well after the operation, the symptoms disappeared and no neurological deficits remained. This type of schwannoma is extremely rare and is highly likely to be misdiagnosed as a brainstem glioma due to its imaging manifestations. This case emphasises the importance of cautious diagnostic evaluation and surgical management of such rare tumours, providing valuable reference for clinical practice.