Solitary Metastasis of Bronchogenic Adenocarcinoma to the Internal Auditory Canal: A Case Report

We report a patient with an isolated metastasis to the internal auditory canal (IAC) of bronchogenic adenocarcinoma. A 58-yr-old man who had received 6-cycle of chemotherapy under diagnosis of non-small cell lung carcinoma (T4N2M0) two years ago was referred to our department with vertigo, right-sided facial paralysis and right-sided hearing loss. A provisional diagnosis of vestibular schwannoma or meningioma involving right IAC was made from magnetic resonance imaging. The patient underwent a translabyrinthine removal of the tumor. Histopathological study of the resected lesion showed a poorly differentiated adenocarcinoma compatible with bronchogenic origin. The patient died 9 months after surgery from extensive brain metastasis despite postoperative radiation therapy. In patients with a previous history of treatment of malignancy elsewhere in the body, the possibility of IAC metastasis must be considered when an IAC lesion is detected.