Bilateral Internal Auditory Canal Metastasis of Non-small Cell Lung Cancer

We report on a patient with brain metastasis involving bilateral internal auditory canal from non-small cell lung cancer (NSCLC). A 49-year-old woman who had been diagnosed with NSCLC (T2aN1MO) complained of persistent vertigo and bilateral tinnitus for three months. The patient had refused all treatments, including surgery and chemotherapy; however, she sought alternative medicine. The patient's hearing loss showed rapid progression bilaterally, and rotatory vertigo with peripheral-type nystagmus developed. Magnetic resonance imaging of the brain showed irregular nodular enhancement within both internal auditory canals with leptomeningeal enhancement and multiple intracranial metastasis. The patient was treated with epidermal growth factor receptor-tyrosine kinase inhibitor, and the tumor showed partial response. This was a rare case of multiple brain metastases involving bilateral internal auditory canal from known NSCLC presenting with vertigo and hearing loss.