Parotid Mucoepidermoid Carcinoma
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Here we have another example of a mucoepidermoid
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carcinoma, in this case, an MRI scan.
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The characteristic features are a
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mass that has irregular borders.
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That on T2-weighted scan is not bright.
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And with gadolinium enhancement, usually
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does show some enhancement. It.
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What we want to do on the scrolling here is to
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identify whether or not there's any lymphadenopathy.
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It's probably best detected on the T2-weighted
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imaging. In this case,
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we have this lymph node which appears to be enlarged
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on the ipsilateral side in level two,
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a jugular chain where I would be
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worried about malignant spread.
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We want to look more superiorly at foramen ovale
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as well as stylomastoid foramen to determine whether or
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not there is any evidence of perineural
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spread up the 7th cranial nerve.
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Or the third division of the fifth cranial nerve,
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the mandibular nerve. In this case, all clear.
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So the thing we have to worry about here is just the
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lymph nodes and that might require separate aspiration
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in this case, in particular post-gadolinium.
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I would say.
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Could I show this case as an example of an oncocytoma?
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I think so. I mean, it kind of vanishes on the T2
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and on the post-gad T1 it kind of vanishes
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into the normal parotid tissue.
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So the vanishing parotid tumor may overlap.
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That is, the oncocytoma may overlap in its signal intensity
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characteristics of some of the malignancies as well.
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In this case,
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because it is relatively dark on T2-weighted scan,
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would be more concerned with a medium to lower-grade,
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lower-differentiated mucoepidermoid carcinoma.
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Most well-differentiated mucoepidermoid carcinomas
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are relatively bright on T2-weighted imaging.
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
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