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Hi everyone, it's Mark, and we are gonna round out our

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pattern recognition with one more distribution talk.

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This one is gonna be focused on the diseases

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that manifest in a bronchovascular distribution.

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Again, distribution is so key in pulmonary

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imaging—it's about location, location, and location.

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And what we're gonna do here is

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discuss about bronchovascular distribution.

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It is useful, and I'm focusing on it because if you

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can recognize that something is radiating out from the

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hilum, your differential just shrunk substantially.

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There's really not a lot of diseases that do this.

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So, we go back—because of the distribution, the pulmonary

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microenvironments—remember, only certain diseases

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tend to manifest in certain parts of the lung.

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This one will be the bronchovascular.

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This is your differential.

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Now, bronchovascular is often a lymphatic-based disease

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process, and it migrates out from the hilum into the lung,

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kind of marching out. And Sarcoid is a poster child of

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it, but so is lymphoma and lymphoproliferative diseases.

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Kaposi's sarcoma—

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it's not "Capsis," by the way.

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He was Hungarian—Kaposi's sarcoma.

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And the last one was DIP.

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And that's these perihilar bronchovascular cysts.

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If it's an acute development of a

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bronchovascular process—usually

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consolidation—start thinking about aspiration.

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So those, those would be sort of your main players.

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So, a patient, non-chronic, non-productive cough.

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Well, it's an intimidating-looking radiograph,

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but if you just kind of breathe for a moment and

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look, you're like, wait a minute—look at this.

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This is radiating out from the hilum, and

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there are multiple pulmonary nodules,

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evidence of scarring.

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Oh my gosh.

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Yeah.

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Sarcoid is most likely.

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Lymphoma.

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I guess it's possible, but lymphoma

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usually doesn't cause a lot of scarring.

2:01

So this was sarcoid. Another patient, perihilar

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nodularity with retraction of the hilum up again,

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telling us it's an upper lobe disease process.

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So you'd look at upper lobe disease,

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bronchovascular, and you go, huh?

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Yeah, this is most likely gonna be stage four sarcoid.

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I guess you could consider silicosis as well,

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but the emphysema is a little off for that.

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Now, what about this? Hodgkin's lymphoma.

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Perihilar bronchovascular, some nodules, almost

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confluent consolidation at some places too.

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That's what it looks like anyway.

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But yeah, this is Hodgkin's lymphoma.

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And Hodgkin's lymphoma characteristically spreads

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from lymph node chain to lymph node chain.

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And if you look at the mediastinum,

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you can see that it's convex, and it's

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the same density as the aortic arch.

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And remember,

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that tells us that there's likely a pathology there.

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In this case, it was enlarged lymph nodes.

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Now, this patient is in the intensive care

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unit and they developed bilateral perihilar

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bronchovascular consolidation within 24 hours.

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Well, geez, that's aspiration pneumonitis,

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and your differential would be aspiration pneumonitis.

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Bronchovascular.

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Now, perilymphatic nodularity,

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which we talked about in the

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earlier session.

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This is an example of bronchovascular

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distribution of perilymphatic nodules.

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Notice they vary in size,

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which tells us, ooh, that could be a tumor.

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And in this case, this was in fact lymphoma.

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This patient has perilymphatic nodularity, beaded,

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all similar in size with a bronchovascular distribution.

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Very characteristic for sarcoidosis.

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Really, I don't have much of a

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differential, silicosis maybe.

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Extensive disease came into the ER, and you look and

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you're like, oh man, I don't even know where to start.

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It just looks terrible.

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Well, stay calm.

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What do you notice?

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A lot of scarring and bronch—

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traction bronchiectasis.

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Okay, so it's a chronic problem.

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It has an upper lobe predominance,

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but what else do you notice?

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Look how it radiates out from the hilum.

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It's got a bronchovascular distribution.

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Cool.

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'Cause the differential is very small.

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And if you were to go a little further, I find when

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you look, well, I'll tell you that in a minute.

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This is what you would do.

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Upper lobe diseases.

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There they are.

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Bronchovascular distribution.

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There they are.

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Well shoot, we only have sarcoid.

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Well, this must be chronic sarcoid.

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And if you happen to look in patients with just

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extensive disease, try to look in the areas of

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less involvement and see if there might be some

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clues to what is driving this disease process.

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And when you look here, you'll notice

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the beaded perilymphatic nodularity here.

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This is sarcoid.

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No differential.

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Now this patient looks a little different.

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They have some subtle ground glass,

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and they have these perihilar cysts.

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He also had a bit of emphysema in the upper lobes.

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So what are these perihilar cysts that seem

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to just kind of radiate out from the hilum?

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And what this is, is characteristic

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for desquamative interstitial pneumonitis.

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Now a lot of people have evidence of emphysema, but.

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They also have these perihilar cysts that

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almost every radiologist calls emphysema.

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It turns out these are not emphysema.

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This is part of the desquamative interstitial

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pneumonitis pattern of injury, which is

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also a smoking-related disease process.

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Okay, so when you see these sort of perihilar cysts,

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recognize them, not as emphysema, but as a manifestation

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of DIP, which you will see this, it's relatively common.

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DIP is considered rare,

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but that's the really severe cases.

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But mild forms of DIP are actually relatively common to see.

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41-year-old male, HIV, bronchovascular distribution.

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What does it look like?

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I'm not sure.

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It's a hard one to describe.

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Ill-defined nodules, maybe some consolidation.

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If it were acute, I'd almost think

6:27

aspiration, but it's not acute.

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When you look here, you see, yeah,

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these are some ill-defined nodules.

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There's some septal thickening, but it has a

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bronchovascular distribution and it also has some

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hyper-enhancing lymph nodes, which is kind of a clue.

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This is Kaposi's sarcoma.

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We don't see this very much anymore, thankfully,

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but if you happen to come across someone who's

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had HIV for a long time, no treatment,

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you know, has the bronchovascular ill-defined

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nodularity, hyper-enhancing lymph nodes.

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That's Kaposi's.

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So last one, 59-year-old female, worsening

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non-productive cough and dyspnea for three months.

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You look and you see these areas of consolidation, maybe

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some ground glass nodularity, but its distribution

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is what's telling, it's bronchovascular, isn't it?

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Now, there's no enlarged lymph nodes.

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I would've thought maybe this is

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cryptogenic organizing pneumonia.

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But she came back and everything progressed substantially.

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And the bronchovascular distribution is marked.

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It almost looks like a spider, right?

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The arachnoid sign or something.

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So this is actually going to be something else.

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And they did a bronchoscopy and got, you know, something.

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So, we'll just throw it up to you.

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What do you think is the most likely diagnosis?

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Well, maybe it's, you know, Kaposi's sarcoma,

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maybe it's sarcoid, primary pulmonary

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lymphoma, or cryptogenic organizing pneumonia.

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And when you kind of look and you're like, wow,

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there's no real dominant nodularity. I don't know.

8:04

It turned out to be pulmonary lymphoma.

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And this is pretty characteristic for lymphoma,

8:10

again, to have this bronchovascular.

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So that distribution would've really helped.

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And if you see even these kind of consolidative

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appearances, sarcoid, I guess is a reasonable one.

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But in this case, they got a bunch

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of lymphocytes on bronchoscopy.

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So summary: Bronchovascular distribution, it's, if you

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can recognize it or if you're aware of it, you will

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have a much more narrow differential, even if you

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have trouble describing what the morphologic pattern

8:41

is, 'cause it's usually going to be one of these.

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With that, I thank you very much, and we'll talk

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to you in later sessions on more specific topics.