Tenosynovial Cyst
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This is a 45-year-old male who has a palpable soft
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tissue mass along the dorsal aspect of the foot.
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And let's put up the sagittal,
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heavily water-weighted image.
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This is not a difficult case, but you'll notice
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that the lesion has a very tubular appearance,
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going up and down for quite a distance.
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And that suggests a specific diagnosis because of
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its intimacy with the extensor tendon mechanism.
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Which includes, in the axial projection,
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the tibialis anterior tendon.
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Next to it is the extensor hallucis,
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and then the extensor digitorum and peroneus tertius.
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You can see how this winds its way around
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the tendon in the axial projection.
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Let's blow that up a little bit.
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It's fairly circumferential, but its true
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tubular nature is not as apparent,
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even on the coronal, as it is on the sagittal.
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So, your first response to
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this should be a tenosynovitis.
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Then the next thing you ought to do is
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call up something that is T1 weighted
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and see if there's anything in it.
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You know, is it purely proteinaceous fluid?
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Is it pure fluid?
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Or does it have synovium or blood inside it?
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And it is not pure fluid,
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because it's pretty close to muscle.
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In fact, it's a little lighter than
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muscle, so it's got to be proteinaceous.
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Yet, it doesn't have any
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synovitis or pannus inside it.
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So your differential diagnosis for something
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like this is mechanical tenosynovitis,
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R.A. J.R.A.
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38 00:01:37,080 --> 00:01:37,360
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I showed you in this teaching set
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a case of granuloma annulare that
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involved the the tendon sheath.
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Psoriasis with giant distention of the,
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of the sheath can produce a sausage digit.
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And then you've got weird things like amyloidosis,
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which can occasionally occur in the tendon sheath.
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But this is a mechanical tenosynovitis,
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very straightforward, circumscribing the tibialis anterior tendon.
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49 00:02:08,590 --> 00:02:10,449 Dr. P out on this one.
Stephen J Pomeranz, MD
Chief Medical Officer, ProScan Imaging. Founder, MRI Online
ProScan Imaging
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