CT AND MR OF TEMPORAL BONE MALIGNANCIES PRIMARY AND SECONDARY TO PAROTID CARCINOMA

PURPOSE: To review the CT and MR characteristics of temporal bone mali gnancy, and to evaluate the relationship between malignancies of the t emporal bone and parotid gland. METHODS: A group of 15 surgical patien ts with diagnosis of temporal bone malignancy were retrospectively rev iewed. These included 11 cases of primary temporal bone malignancy and four cases of secondary carcinoma of the temporal bone from a primary tumor of the parotid gland. Three primary temporal bone malignancies were recurrences, and two secondary tumors were parotid recurrences. R ESULTS: Five of the 11 patients with primary temporal bone malignancy had parotid infiltration (45%). All four patients with secondary tempo ral bone destruction caused by parotid carcinoma had erosion of the ma stoid, two with erosion of the external auditory canal, and one of the middle ear. CONCLUSIONS: It is important radiographically to recogniz e the close relationship between malignancies of the temporal bone and parotid gland, because either may secondarily invade the other. Suspi cion of malignancy in either the temporal bone or parotid gland necess itates complete imaging of the other structure. Temporal bone or skull base erosion were best seen on CT at bone algorithm. MR with and with out infusion provided excellent delineation of soft-tissue tumor margi ns, muscle infiltration, intracranial extension, and vascular encaseme nt.