Metastatic tumors in the temporal bone--a pathophysiologic study.

Nineteen temporal bones were examined from 11 patients who had metastatic temporal bone disease from a distant primary. The salient clinical features were: the high incidence of occult temporal bone involvement (7 of the 10 clinically documented cases), the considerable incidence of melanoma (3 of 10) and the variable correlation between clinical findings and pathologic localization of tumor in the temporal bone. Pathologic examination revealed two distinct modes of tumor spread within the temporal bone: 1) vascularosseous (petrous apex, mastoid, middle ear, external canal); and 2) perineural (nerves in IAC branches, labyrinthine endorgans). Every case was involved by one or both or these routes and no case of CSF-borne metastasis to the perilymphatic space was seen. The external canal was involved extensively in spite of an intact tympanic membrane. Since the presence of symptomatic or occult metastases in the temporal bone affects treatment and prognosis, they must be actively sought by the clinician.