[Histopathological study of the temporal bones in patients with primary carcinomas of the ear]

The most common symptoms of patients with carcinomas of the middle ear or mastoid are otorrhea, facial paralysis, and hearing loss, including a sensorineural element and vertigo. The latter two symptoms are indicators of inner ear damage. However, few reports have been made concerning the histopathological changes that occur in the inner ear in the presence of a tumor. The present study was performed to determine the pattern of tumor invasion in the inner ear and the histopathological changes that occur in the inner ear in cases of ear carcinomas. Temporal bone sections from five patients (age: #39-73 years; 3 males and 2 females) who died from a primary carcinoma of the ear were studied histologically. The following features were examined: 1) localization of the tumor in the temporal bone, 2) pattern of tumor invasion in the inner ear, 3) pathological changes in the inner ear, including the cochlea, vestibule and semicircular canals. Tumor cells were still present in the temporal bone sections of all the patients except one, even though the patients had received various treatments for the carcinoma, including radiation therapy, surgery and chemotherapy. Marked inflammatory and necrotic changes were observed in cases where the tumor had invaded the external auditory canal, middle ear cleft, internal auditory canal, and in some cases the inner ear. In cases where the tumor invaded the inner ear via the internal auditory canal rather than directly from the middle ear, the otic capsule is thought to have acted as a barrier against tumor invasion. In addition, marked degenerative changes throughout the entire inner ear structures were noted. These changes may have arisen from an attenuated blood supply to the inner ear as a result of pressure from the tumor in the internal auditory canal, tumor infiltration of the labyrinthine artery.