ASHNR '98'

uhrad.com - Case #3

Clinical History: A 53 year old female presents with a 5-10 mm mass in the EAC. It does not appear to be particularly vascular

Benign Mixed Tumor of the Parotid

Findings: There is a 1 to 2 cm. mass which projects into the right external auditory canal. It is solid appearing with intermediate signal and homogeneous enhancement on T1 weighted images before and following contrast injection but is quite bright on T2 weighted images as well. The differential diagnosis could include mucosal or cartilaginous lesions of the external auditory canal. A tumor of neurogenic origin originating from the 7th nerve would be expected to extend into the external auditory canal from posterior rather than anterior. Since parotid tumors are so much more common than tumors of the external auditory canal, this should be the leading diagnosis. Benign mixed tumors comprise 50% of all parotid tumors and are most common in females between the ages of 30 and 70. The signal characteristics and enhancing qualities seen on MR are typically illustrated in this case.

Reference:
Ikeda. AJNR 1995;17:555-559.

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