0:00

Let's take a look at this lung cancer screening ct.

0:04

Together at the apices, we're seeing some septal

0:07

and central ular emphysema

0:09

and a few sub centimeter, two to four millimeter

0:13

by apical lung nodules.

0:14

Those would be considered category two in lung rads.

0:17

Here's another small sub six millimeter nodule on a first

0:22

time CT or four millimeters and smaller on a subsequent ct.

0:26

So lots of background, tiny pulmonary nodules.

0:30

We're seeing a ground glass nodule here

0:32

and the loft upper lobe looks like it's about

0:34

eight to 10 millimeters.

0:35

We can certainly measure that.

0:38

We get about 10 millimeters in its longest diameter.

0:42

And then we come into the superior segment

0:44

of the left lower lobe.

0:46

And let's magnify this up a little bit.

0:48

We see something that has a broad surface of contact

0:51

with the pleural surface.

0:53

It looks somewhat almost triangular geographic,

0:56

but we see some discreet cysts in it.

0:58

Here's the largest cyst

1:00

and that measures it measures about five

1:03

and a half millimeters.

1:05

And then we have some smaller cysts within it lining

1:08

the pleural surface there.

1:09

And notably, we don't see any paraseptal emphysema nearby.

1:12

We don't see any emphysema actually at all at this level

1:16

in the person's lungs.

1:18

We have this cyst

1:19

and if we look really closely,

1:21

let's measure that one a little bit more.

1:22

Yeah, about six millimeters.

1:25

It's got a little bit of a septation

1:27

right across the middle of it.

1:28

So we've got some severing size,

1:30

largest about six millimeter, one with a little bit

1:33

of internal septation

1:35

and the rest of the nodules kinda in glass.

1:38

Now let's see, as we keep looking at the lungs,

1:43

looks like that's pretty much it.

1:45

We'll put on our mips. Help us find other nodules.

1:49

You see a bunch of those tiny two

1:51

to three millimeter nodules

1:52

that went all fonder lung rides too.

1:56

So this seems to be the biggest nodule of concern.

1:59

This area here in the left lower lobe super segment together

2:02

with that ground glass nodule there in the left upper lobe.

2:04

So we're gonna wanna look at comparisons

2:06

to see what's been changing over time.

2:09

'cause biologic behavior, we see that in terms of growth,

2:13

there's that ground glass nodule in the left upper

2:16

lobe that hasn't changed.

2:18

It's under 30 millimeters, so that's gonna make,

2:21

that's a long RADS two type of lesion.

2:23

But if we look at the cystic area, these side

2:27

by side a little bit, we can see there was something there

2:30

in the lung before it had some little cysts in it,

2:35

but they were smaller and there were fewer of 'em.

2:37

And the overall size of this lesion is increased.

2:41

We can try and measure it.

2:43

It's a little tough 'cause it's low on the pleural surface.

2:46

It's about just about 20 millimeters along the pleural

2:49

surface and in depth about 10 millimeters.

2:53

And we can measure before get about

2:56

16 millimeters along the

2:58

Pleural surface.

3:01

And about the same depth.

3:03

Well, no, a little bit narrow in depth too, so it's shorter,

3:06

it's not as thick and not as wide.

3:09

So it's bigger, it's got more cysts

3:11

and the cyst increased in size since our comparison exam.

3:16

And these are comparisons.

3:17

We've got, I think this is April 21 on the left.

3:21

We've got October, 2018 on the right.

3:24

So we've got more than a couple years here, two plus years,

3:28

and it's definitely grown.

3:29

So if we apply our nomenclature for multilocular cysts,

3:34

the size of the lesion is increased

3:36

and the cyst size is increased.

3:38

That makes this um, a category four B lesion

3:42

because of the increase in size and increase in both size

3:45

and number of cyst.

3:46

That's the highest category of recommendation.

3:49

This patient did subsequently undergo a left lo lobe,

3:53

superior segmentectomy,

3:55

and this was a grade one,

3:57

a well differentiated adenocarcinoma.

4:00

And three years out now from surgery,

4:02

the patient has no evidence of a recurrent lung cancer

4:06

or new evidence on their lung cancer surveillance exams.

4:10

So this is an example of a multilocular cyst,

4:14

increase in size of cyst, increase in number of cysts,

4:17

and increase in overall size of the lesion.

4:20

I think historically we really didn't know what to do

4:22

with these, but it really points out

4:24

what looks like a little subpleural cystic area

4:26

with thickening is actually a well differentiated

4:29

adenocarcinoma and very important to be attentive

4:32

to those features.

4:33

Size overall number of cyst overall

4:37

and size of cyst is three important things to measure

4:41

in these complex cystic nodules.

4:43

One last comment about this case.

4:45

A pet CT was done for assessment,

4:48

but there was no significant activity in the lesion.

4:52

It can be very hard on PET CT to understand these tumors

4:56

because the cyst is the predominant area.

4:59

There's not a lot of tissue density, there's not a lot

5:02

of published literature on the use of pet CT

5:05

in cystic lesions.

5:08

We know that ground glass nodules, for example,

5:10

can be false negative on pet.

5:12

Again, just not enough dense cellularity

5:14

to take up enough glucose to get a signal.

5:16

And the same thing can happen with these cystic nodules.

5:19

So here's the PET scan.

5:21

Just a little bit of activity here,

5:23

not any greater than blood pool,

5:24

so be considered a negative PET ct.

5:27

So just like ground glass nodules

5:29

where we don't accept a negative uptake as an indicator

5:34

of benignity and we shouldn't accept a negative PET scan

5:37

as indicator of benignity in cystic lung nodules due to

5:42

that cystic component not having much tissue in it.

5:44

To take up the FDG PET tracer.