Interactive Transcript
0:01
In a prior vignette, I showed you a case
0:03
of osteoblastoma that involved the patella.
0:07
So this case is the younger cousin of
0:10
osteoblastoma, which is an osteoid osteoma.
0:14
It's in a somewhat unusual location because
0:17
if you do have osteoid osteomas in the
0:20
foot, it typically involves your talus,
0:23
and typically near the head-neck junction.
0:25
That's a very, very common
0:27
location for an osteoid osteoma.
0:29
But this one has occurred right here.
0:32
So this is your calcaneus,
0:35
that makes this your cuboid.
0:37
It has a very characteristic appearance.
0:39
There is a central area of low
0:42
density, which is the nidus.
0:44
Surrounded by an area of calcification,
0:48
which is a reaction, sclerosis,
0:50
to the act of inflammation.
0:52
You can see that those signal, or, excuse
0:54
me, the low-density nidus here, again,
0:56
with some, with some calcification.
0:58
And there's also sclerosis
1:00
in the surrounding bone.
1:02
That sclerosis, if you notice, is a little
1:04
brighter, or a little denser, than the rest of
1:07
the trabecular pattern that you see in the bone.
1:09
So that is going to correspond
1:11
to an area of intense edema.
1:13
Here is the coronal view of the same area.
1:17
This is our nidus with an area of
1:21
calcification and surrounding sclerosis.
1:24
Typically, this is where it occurs.
1:26
It occurs at the very edge of the bone.
1:28
Some people think it's a process
1:31
that happens just under the periosteum,
1:34
and I think that's probably true because
1:36
the majority of these lesions, in fact, are
1:38
located very close to the periphery of bones.
1:42
Now if we look at the MRI, I'm going
1:44
to blow this up for you a little bit.
1:46
Look at the entire bone of your cuboid.
1:51
The whole thing is bright, so there's a lot of
1:53
intense inflammatory reaction that this elicits.
1:57
Again, you can see that there is that
1:59
nidus up here at the very periphery.
2:02
The nidus is often much better seen on a CT scan.
2:05
And that's why when we see something that
2:07
may be an osteoid osteoma on MRI, and we're
2:12
unconvinced that we actually see a nidus or
2:14
there's something else that's obscuring the
2:15
nidus, we will recommend the CT scan because
2:18
that is a much better modality to look at
2:22
the bony architecture and the nidus itself.
2:25
MRI is helpful to look at the edema.
2:27
The CT is great to look at the
2:29
bony nidus, and for radiofrequency
2:32
ablation or surgical planning.
© 2024 MRI Online. All Rights Reserved.