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This was a 32-year-old individual who presented

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with soft tissue mass in the right external

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auditory canal, as well as conductive hearing

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loss. As you look at this case,

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which is a contrast-enhanced

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CT scan with thin images,

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we see that there is a process which is

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extending from the bony portion of

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the external auditory canal,

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and it appears to have associated opacification

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in the middle ear cavity as well,

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and maybe a little bit of soft tissue

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into the mastoid air cells.

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So if we look at the external auditory canal

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on the bone windows and magnified view,

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we see that there is erosion which is occurring

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along the posterior margin of the external

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auditory canal, and there also appears to be

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expansion of the external auditory canal

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and extension into, as I mentioned,

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the mastoid air cells and the middle ear cavity.

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Here we see middle ear ossicles

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outlined by soft tissue. Now,

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when you have an expansile mass that

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is in the external auditory canal,

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you have a relatively broad

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differential diagnosis.

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So we've talked about the entities of keratosis

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obturans, as well as cholesteatoma.

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Why would this be not one of them?

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Well, as I mentioned, with keratosis obturans,

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usually you have a phenomenon which is largely

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expansion without so much bony erosion.

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In this case,

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the large amount of bony erosion posteriorly

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would argue against this being

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a keratosis obturans case.

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A cholesteatoma could be a possibility,

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in that there is that erosion of the bone.

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However, the expansion is a little bit atypical

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for the cholesteatoma.

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However, I think one of the features that I think is

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important to evaluate in this case is the fact

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that we see that there is contrast

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enhancement of this lesion.

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So contrast enhancement would be unusual

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in a cholesteatoma. If it occurs,

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it's usually around the periphery.

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It's also unusual in keratosis obturans.

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So I would shift my focus and...

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you know, first off, ask the clinician,

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do you see something that's vascular in there?

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And maybe suggest that this could be like a

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hemangioma or venous vascular malformation.

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This patient's case is a little bit atypical in

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that this ended up being a fibrovascular polyp

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of the bony portion of the external

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auditory canal. As you can see,

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the process that's going on in the middle

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ear cavity, which is non-enhancing,

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was secondary inflammation,

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but the primary process was a fibrovascular

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polyp, which was both eroding and expanding

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the external auditory canal.

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And the important imaging feature is the

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presence of that contrast enhancement.