Primary glioblastoma of the cerebellopontine angle in adults

Gliomas are rare entities in the cerebellopontine angle (CPA) in adults. The authors present clinical, neuroradiological, serological, and neuropathological findings in a 60-year-old man with an extraaxial CPA glioblastoma arising from the proximal portion of cranial nerve VIII. The patient presented with progressive left-sided deafness and left-sided facial palsy lasting less than 2 months and progressive dysarthria and dysphagia lasting 2 weeks. Preoperative neuroimaging suggested the diagnosis of CPA meningioma with "dural-tail" sign and involvement of the internal auditory canal. Serological examination showed an increase in the malignant markers of ferritin and neuron-specific enolase, which suggested underlying malignancy. The tumor was subtotally removed, and it was confirmed to be completely separated from the brainstem and cerebellum. Cranial nerves VII and VIII were destroyed and sacrificed. Transient severe bradycardia occurred during surgery due to entrapment of the caudal cranial nerve complex by the tumor in such an infiltrative way. The neuropathological examination revealed a glioblastoma. The patient underwent no further treatment and died of cachexia 2 months postoperatively. To the authors' knowledge, this represents the first case of a primary glioblastoma in the CPA in an adult. A high index of suspicion along with reliance on clinical assessment, radiological findings, and serum detection of specific malignant markers is essential to diagnose such uncommon CPA lesions.