Bilateral Hearing Loss Due to Metastatic Gastric Signet Cell Adenocarcinoma Involving the Internal Auditory Canal and Cerebellopontine Angle.

Intracranial metastases of stomach cancers are very rare and are associated with a poor prognosis. Of those, metastases of gastric cancers in the internal auditory canal and cerebellopontine angle represent an extremely rare subgroup. Such metastatic lesions may be indistinguishable from vestibular schwannomas in imaging studies and clinical presentation. In this report, we describe a case of gastric signet cell adenocarcinoma metastasizing to the internal auditory canal and cerebellopontine angle bilaterally and causing bilateral hearing loss, including a unilateral sudden deafness. Due to the co-detection of multiple other intracranial masses in the magnetic resonance imaging scan, the suspected diagnosis of leptomeningeal metastatic disease was clear, and the patient was referred to palliative whole brain radiotherapy. The case further highlights the importance of prompt diagnosis and treatment of metastatic cerebellopontine angle lesions to prevent permanent neurological sequelae. Metastatic tumors should therefore be considered in the differential diagnosis of cerebellopontine angle lesions, especially in patients with a known history of malignant disease.