Isolated metastatic melanoma of the cerebellopontine angle: case report

Malignant melanoma is a common cause of central nervous system metastases. This report describes an extremely rare case of metastatic melanoma presenting as an isolated cerebellopontine angle tumor. Clinically and radiographically, the lesion mimicked an acoustic neuroma. The patient had neuro-otological symptoms, including tinnitus, vertigo, sensorineural hearing loss, facial nerve dysfunction, and prominent cerebellar dysfunction. Magnetic resonance images showed a lesion of the internal auditory canal and cerebellopontine angle that was hypointense on T1-weighted images, hyperintense on T2-weighted images, and enhanced after the administration of gadolinium. T2-weighted images showed significant cerebellar edema. Subtotal resection of the tumor through a suboccipital craniotomy palliated the symptoms, but the patient died of tumor progression 6 months later. In contrast to other metastatic tumors of the temporal bone, melanoma initially metastasizes to the internal auditory canal and is characterized by early neurovascular infiltration. This report highlights the pathophysiological characteristics, radiological findings, differential diagnosis, and treatment of metastatic melanoma of the internal auditory canal and cerebellopontine angle.