MR and CT of squamous cell carcinoma of the middle ear and mastoid complex.

Squamous cell carcinoma infrequently arises in the middle ear and external auditory canal. Mastoid complex primary carcinoma is extremely rare. The site of origin of these tumors may be obscure when large destructive lesions are encountered at the initial presentation. Imaging techniques may provide a clue as to the origin of these carcinomas. The complementary role of CT and MR is illustrated in two cases: one with primary carcinoma of the mastoid complex and the other with carcinoma of the external auditory canaljmiddle ear. The sclerosis of bone evident on CT and the striking dural enhancement seen by MR in these cases is discussed.