Computed tomography and magnetic resonance imaging findings for primary middle-ear carcinoma.

OBJECTIVE: This study aimed to investigate the computed tomography and magnetic resonance imaging findings of primary middle-ear carcinoma.
METHODS: In this retrospective study of 13 patients with primary middle-ear carcinoma, we collected pre- and post-contrast magnetic resonance images for all 13 cases, high-resolution computed tomography scans for 11 cases, and conventional computed tomography scans with contrast for 2 cases.
RESULTS: Soft-tissue masses were mainly located in the tympanum, tympanic sinus and deep within the external auditory canal, and involved the jugular fossa (9 of 13 patients), middle cranial fossa (5/13), parotid gland (2/13) and temporomandibular joint fossa (1/13). An irregular, 'moth-eaten' bone destruction pattern was seen on high-resolution computed tomography images, most commonly in the eustachian tube (9/13), jugular foramen (9/13) and facial nerve canal (7/13). On non-contrast magnetic resonances images, masses were isointense or slightly hypointense on T1-weighted images, and isointense or slightly hyperintense on T2-weighted images. On post-contrast images, lesions were moderately and homogeneously enhanced in seven cases and inhomogeneously enhanced in six.
CONCLUSION: High-resolution computed tomography precisely detects regions of bone destruction, whereas MRI can better assess soft-tissue tumour margins, intracranial extension and vessel patency. Eustachian tube erosion is an important characteristic of primary middle-ear carcinoma.