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Here's a case of a teenager who presented

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with vague, diffuse pelvic pain.

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Ultrasound was performed; it was negative,

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and then plain radiographs were obtained, and

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this is what I'm showing to you right now.

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As you can see, or maybe you can't

0:19

appreciate, but the more you look at

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this, the more you'll realize that the

0:24

appearance of the bone is not normal.

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And it's not just one bone.

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It's the entire bone, right?

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There's areas of lucency

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intermixed with areas of sclerosis.

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And it's not just involving the right

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femur or the left femur or the iliac

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wings or acetabulum or the, or the

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obturator area, ischial tuberosity.

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It's sort of diffuse.

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And unless you sort of pick

0:46

up on that, it can be missed.

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It was first looked at by a non-

0:51

radiologist and was called normal.

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But when it came to our attention, we said,

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you know what, this looks a little funny.

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So let's investigate this a little bit more.

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Okay.

0:59

Uh, by the way, there's a little avulsion injury

1:01

right over here that, in case you missed it,

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and hopefully you looked at the prior vignettes

1:05

showing that, but that's not the issue here.

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The issue here is a very abnormal appearance

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or, or, or brightness of the bone.

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So for that reason, we ended up getting an MRI.

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For the MRI, in the middle we have a T1-

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weighted sequence, and on the right we have

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a fat-suppressed, fluid-sensitive sequence.

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So, I'm going to zoom up on

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just the T1-weighted sequence.

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You notice there is diffuse bony abnormality.

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Both femurs, ilium, even the vertebral

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bodies, they demonstrate a very heterogeneous

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appearance in their matter, marrow.

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Now, if you look at the marrow, for

1:45

example, uh, in, on the right side, right

1:49

femoral neck, uh, femoral head area.

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And compare it to muscle,

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it's actually quite similar.

1:55

So we were a little stumped, when

1:57

could this just be some funny edema?

2:00

Uh, but it just looked abnormal.

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It just didn't look like, because

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edema shouldn't be patchy like this.

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And it shouldn't cause these

2:08

areas of serpiginous abnormality

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that you see in the femoral head.

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And this is some early signs,

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MR, of avascular necrosis.

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So whatever is happening is clogging up the

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vessels that are feeding these femoral heads.

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The femoral heads are actually quite sensitive

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to decreases in perfusion, so this is

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causing some degree of avascular necrosis,

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and that's what you're seeing over here.

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Similarly, lots of abnormality in the pelvis.

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This person eventually got biopsied,

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and this ended up being leukemia.

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So sometimes leukemia infiltration

2:47

may not quite be dark enough such that

2:51

it's darker than the adjacent muscle.

2:53

So that's one of the caveats, but the

2:55

pattern of such diffuse involvement over

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multiple bones is highly suspicious for

3:01

an infiltrated process such as leukemia.

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I'm just going to show you, uh, for the sake

3:05

of completeness, what the STIR signal showed.

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Again, the STIR signal here shows

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areas of serpiginous, low signal

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corresponding to some avascular necrosis.

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Irregular areas of brightness

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intermixed with dark areas, again

3:21

showing an infiltrative process.

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There may be a small joint effusion bilaterally.

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And once we gave contrast, I think

3:28

it becomes abundantly clear that

3:30

this is just not normal bones.

3:32

Look at the serpiginous areas of

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enhancement, lack of enhancement altogether,

3:36

meaning that there's avascular necrosis.

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Enhancement of the synovium, so that

3:40

joint effusion was a little reactive.

3:43

And also abnormal enhancement of

3:46

the iliac bones and the mottled

3:48

appearance of the vertebral bodies.

3:50

So this is leukemia.