The histopathological findings in the temporal bone of a 75-year-old woman, who was diagnosed with carcinomatous meningitis of an unknown origin, were reported. The histopathological diagnosis of her tumor was papillary adenocarcinoma. She complained of hearing loss in the left ear, but there was no history of tinnitus or dizziness in her medical records. Regrettably, audiometric and vestibular function tests were not carried out. There was infiltration of tumor cells in the surrounding area of the cochlear, vestibular and facial nerves. However, there were only a few tumor cells infilirated into the cochlea and vestibule. It was thought that the tractus spiralis foraminosus and macula cribrosa functioned as a barrier by preventing tumor cells in the cerebrospinal fluid from penetrating into the cochlea and vestibule.
