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Hello and welcome to noon

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conferences hosted by MRI Online.

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In response to changes happening around the world

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right now and the shutting down of in-person

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events, we have decided to provide free daily

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noon conferences to all radiologists worldwide.

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Today we are joined by Dr. David Bloom.

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Dr. Bloom is a clinical pediatric radiologist

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specializing in pediatric oncological

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and genitourinary imaging at Michigan

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Medicine - C.S. Mott Children's Hospital.

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A reminder that there will be a Q and A session

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at the end of the lecture, so please use the

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Q and A feature to ask your questions and we will

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get to as many as we can before our time is up.

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That being said, thank you all

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for joining us today. Dr. Bloom,

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I'll let you take it from here.

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Thank you very much and, uh, I'd like to first thank

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MRI Online for inviting me today to talk to you about

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pediatric abdominal tumors, abdominal masses.

1:00

And I am going to share my screen.

1:03

Uh, so we're gonna talk today about

1:06

pediatric abdominal masses.

1:07

And obviously there is so much

1:10

that we could cover in one hour.

1:12

I've sort of, uh, found a couple of important

1:16

topics to try and review, as well as to, uh,

1:20

really hone in on some of the ways to think

1:22

about abdominal mass imaging, especially with

1:25

regards to the use of MRI in pediatric patients.

1:29

I do not have any disclosures.

1:31

So our objectives today will have an

1:34

introduction to imaging and techniques.

1:36

We're going to review some of the more common

1:38

pediatric abdominal tumors, uh, and then

1:41

outline some of the differential diagnoses.

1:43

And I've sprinkled throughout the talk some tips

1:47

and helpful hints that hopefully will, uh, uh,

1:50

make it a little bit easier for you to really, uh...

1:54

Uh, come to a correct diagnosis and

1:56

really help your referring physicians

1:58

with pediatric abdominal masses.

2:02

So the approach, uh, in this modern age of

2:06

teleradiology and remote, uh, interpretation

2:11

and advanced cross-sectional imaging with CT

2:14

and MRI, um, we sometimes lose sight of the

2:17

plain radiographs and their value to us.

2:20

Uh, when taking a look at patients who have

2:22

abdominal distension or, uh, palpable abdominal masses

2:26

or suspected masses, so I find them always helpful.

2:30

Um, oftentimes they will be obtained because we're

2:32

looking at gas pattern, we're looking at other

2:36

things that might help to explain the patient's

2:39

abdominal discomfort and abdominal distension.

2:42

So you can look for calcifications.

2:45

You can start to hone in on the location

2:47

of the abdominal mass based on the

2:49

radiographs, and then the ancillary findings.

2:51

And I'll show you some examples in pediatric imaging.

2:54

As you are all aware, because of portability,

2:58

lack of ionizing radiation, and its high spatial

3:02

resolution in small patients, ultrasound is

3:05

almost always our next imaging step.

3:08

Once the ultrasound's done and determines

3:09

that there is a mass, then the key is,

3:12

well, are we gonna go to CT or MRI?

3:14

And there's, uh, always a conversation

3:17

that occurs with regards to that.

3:19

And we're gonna go over that a little bit more.

3:21

So our first tip: the radiograph can be your friend.

3:25

And so if we take a look at these two images,

3:28

um, we see that there's clearly mass effect

3:31

within the abdomen.

3:33

And if we take a look at the image on

3:34

your right, there might be hepatomegaly,

3:37

maybe perhaps there is a mass.

3:39

We can start to look for other findings

3:41

such as, do we lose any fat planes?

3:44

For example, the psoas margin or the retroperitoneal

3:47

fat planes higher up by the crura of the diaphragm.

3:51

We can clearly see that there's mass

3:52

effect and the bowel is pushed over. When

3:55

the colon especially is pushed over,

3:58

we often think about retroperitoneal tumors.

4:00

In this case, this is a patient with a known

4:03

neuroblastoma at subsequent imaging.

4:06

If we take a look at this image on your left, uh,

4:09

we can clearly see that there's

4:11

mass effect with the bowel gas displaced far over.

4:15

And if you really pay close attention, you can

4:17

actually make a likely diagnosis of what the

4:20

actual tumor's gonna be just on the radiograph.

4:22

So if you pay careful attention, the first thing that

4:26

you see is the mass effect, but then you also notice...

4:31

There are pulmonary nodules and masses present,

4:35

knowing what is likely to metastasize to the lungs

4:37

and what is likely a retroperitoneal mass based

4:40

on the displacement pattern of the bowel and the

4:43

loss of the psoas margin, such that it's telling

4:46

us it's a retroperitoneal tumor — likely renal,

4:49

likely Wilms tumor, which this turned out to be.

4:53

Now, if we were to try and cover in one hour all

4:56

the neonatal, infant, and older child abdominal

4:59

masses, we would be going super fast — speed of light.

5:03

And as you can see from this

5:05

list, just for the neonate.

5:06

Many masses are gonna be benign.

5:08

So, for example, a multicystic dysplastic kidney

5:11

for a renal origin, or a severe hydronephrosis.

5:14

Many of this is already known by prenatal imaging.

5:18

Uh, there are other, uh, renal tumors

5:20

besides Wilms tumors, which are rare

5:22

in the neonatal period, but do occur.

5:24

We're usually thinking more about adrenal,

5:26

non-renal retroperitoneal in origin, such as

5:29

neuroblastoma or retroperitoneal teratoma,

5:32

with neuroblastoma much more common.

5:34

Again, we can have masses related to the genital

5:37

tracts, such as hydrometrocolpos or hydrocolpos,

5:41

large ovarian cysts in utero, ovarian torsion.

5:44

With enlarged cystic ovaries, we can have

5:48

gastrointestinal masses, such as duplication cysts.

5:51

We're really gonna concentrate on the tumors today.

5:55

As we get to older infants and children, we're

5:57

talking about things like, uh, renal Wilms tumor,

5:59

and other renal tumors that occur in the pediatric

6:02

population, which we'll discuss. Again, neuroblastoma.

6:06

But as the child gets older, neuroblastoma

6:08

becomes a little less likely statistically,

6:10

although still a common tumor.

6:13

Uh, and then again, the genital

6:15

tract, the gastrointestinal tract,

6:17

we can even have pancreatic masses.

6:19

Uh, and so again, too much to cover in one

6:22

hour, but we're gonna try and hit some of the

6:24

more common lesions that you might encounter.

6:28

Now, when choosing your imaging, we said

6:30

you're gonna have potentially radiographs,

6:33

and then you're gonna have an ultrasound that

6:34

tells you that there's a mass present, and

6:36

it'll tell you potentially organ of origin.

6:39

It may have already told you about metastatic

6:41

disease to the liver and adenopathy.

6:44

So we now need to decide, are we

6:46

gonna go to CT or are we gonna go to MRI?

6:49

Now we do do a lot of MRI imaging

6:51

because of the ionizing radiation

6:53

issue with regards to CT.

6:56

However, there's always checks

6:58

and balances to this decision.

7:00

So, for example, you might avoid ionizing radiation,

7:04

but you do need to take the risk with sedation

7:06

or general anesthesia for MRI, depending on the

7:09

patient's age and their ability to cooperate.

7:12

Also, what is the staging for that particular tumor

7:15

that you suspect based on your ultrasound, and what

7:19

would be the quickest, most efficient, and most

7:21

effective way for you to answer all the questions

7:24

the oncologist needs with regards to staging?

7:27

So what needs to be identified?

7:29

What questions are still left to be answered?

7:32

What about the timing of the exam?

7:34

If this needs to be done on an urgent basis,

7:36

say, for example, a patient is dropping their

7:37

hematocrit from a cystic Wilms tumor that's

7:40

hemorrhaging, um, do you wait for MRI or do

7:43

you go quickly to CT, which is a much faster

7:45

exam and therefore safer for the patient?

7:49

What is the likely diagnosis based on

7:51

your ultrasound and your clinical history?

7:53

And again, this may alter your decision.

7:56

So, for example, if you think it's a Wilms

7:58

tumor — we just showed an example that

8:00

Wilms tumor does metastasize to the lung —

8:03

we know that with current technology, MRI

8:06

is not as effective for small pulmonary

8:08

masses and nodules compared to CT.

8:11

So if you do an MRI for Wilms tumor for the

8:14

abdominal imaging, you then are still gonna have to

8:16

do a CT of the chest to look for pulmonary metastases.

8:20

Whereas if you did the CT of the chest, abdomen,

8:22

pelvis, it would be fast, effective, one-stop shopping.

8:27

And again, this is gonna be important to

8:28

discuss with your referring physicians.

8:31

Uh, trying to determine what is

8:32

the most effective way to go.

8:34

In general, we try and do MRI as much as we

8:37

can because of the ionizing radiation issue, and

8:40

especially in follow-up with these patients,

8:42

because they will be getting repetitive exams.

8:45

Resource availability.

8:46

And how urgent is the exam?

8:48

And what do the national protocols tell the

8:51

oncologist that they're gonna need for appropriate

8:53

staging and for inclusion in a particular protocol?

8:58

Now, as for the MRI protocols, they can vary.

9:00

They're gonna be tailored.

9:02

We wanna make them as short as possible,

9:03

especially if we're using sedation or anesthesia.

9:07

Typically, the key components are gonna be a

9:10

T1-weighted image, a T2 fat-saturated image.

9:14

Uh, diffusion-weighted imaging

9:15

has become very helpful recently.

9:17

And then post-gadolinium T1 fat-saturated

9:21

images. The fat saturation is usually

9:23

very helpful for really showing you the

9:27

amount of enhancement a tumor may have.

9:29

If you need additional vascular sequences,

9:31

you can do that with dynamic imaging,

9:33

uh, post-contrast, or use bright or

9:36

black-blood technique in order

9:37

to help, uh, make that determination.

9:41

Do you need breath holding?

9:42

Uh, is respiratory motion

9:44

issues gonna be in play? Most of the time,

9:48

you can do almost all of your

9:49

imaging with a 1.5 Tesla magnet.

9:51

However, there are some advantages

9:53

to using 3T. Contrast choices—

9:57

you know, there's debates about safety

9:59

with regards to the potential for NSF

10:02

and using either linear or macrocyclic agents.

10:05

Sometimes for the liver tumors, we even

10:07

use hepatobiliary agents such as Eovist.

10:11

Now, the timing of the sedation and anesthesia may

10:14

need to be coordinated with other imaging needs.

10:17

So, for example, the patient may also need

10:20

a PET/CT, or they may be having an operative

10:22

intervention or an interventional radiology

10:24

procedure that needs to be coordinated so that

10:27

they're under one, uh, anesthesia or sedation.

10:29

So again, there's no right answer to

10:31

say it's always MRI or it's always CT.

10:35

There are certain things that you

10:36

have to balance and think about.

10:39

So let's start with some of the

10:41

more common tumors we do see.

10:43

And, uh, this talk would be

10:45

incomplete without a discussion—

10:46

a good discussion—about neuroblastoma.

10:49

So, neuroblastoma is a common solid neoplasm

10:53

in children in terms of the likelihood of type

10:57

of tumor that a pediatric patient gets.

10:59

It's number three overall,

11:00

behind leukemia and CNS tumors.

11:04

The median age is about two years.

11:06

Most cases are usually diagnosed

11:08

by the age of five.

11:11

Uh, neuroblastoma arises from sympathetic chain

11:14

or adrenal medulla — neural crest-derived tumor.

11:18

And a simple two-thirds rule is that two-thirds

11:21

of neuroblastoma will arise in the abdomen, and of

11:25

those, two-thirds will arise in the adrenal region.

11:28

Uh, they can also occur in other locations along the

11:30

sympathetic chain, especially in the region of the

11:33

organ of Zuckerkandl at the hypogastric plexus.

11:37

Neuroblastoma does metastasize. It goes to bone,

11:41

uh, and that's specifically cortical bone,

11:43

bone marrow—

11:44

and we're gonna talk about that difference—

11:46

liver, lymph nodes,

11:49

and then there are skin manifestations.

11:51

Uh, sometimes patients will present

11:53

with the blueberry muffin appearance.

11:58

Staging.

11:59

There have been several revisions to the

12:01

staging that is used for neuroblastoma.

12:03

I'm gonna show you one of the more

12:05

current ones that is used. In the past,

12:08

we used the Evans staging system, and I will point

12:10

out that metastatic disease in general was stage 4.

12:14

There was a subtype, which we are gonna talk

12:16

about, called 4S, where you had a primary

12:20

tumor that was more like stage 1 or 2, and

12:23

there were metastases to the liver or the skin,

12:28

or the bone marrow — not the cortical bone.

12:30

And we'll talk about that difference.

12:32

And those patients were less than a year of age.

12:35

Uh...

12:36

In that case, 4S in many cases

12:40

had a better prognosis than stage 4 disease.

12:43

It had a different biological behavior, which

12:45

we still don't fully understand, but we do know

12:48

it still occurs under the new staging system.

12:51

Unfortunately for neuroblastoma, in terms of

12:53

prognosis, about 50% of patients are usually in a more

12:57

advanced stage at the time of their initial diagnosis.

13:00

Now, I've, uh, referenced a great

13:03

INRG Task Force report from 2009,

13:07

and this discusses the new staging system.

13:10

And as you can see, it's localized

13:11

disease or M for metastatic disease.

13:14

And the 4S in the old system

13:16

is now MS — under 18 months of age.

13:20

And again, you can have skin lesions, liver lesions,

13:25

or bone marrow metastases, and we'll talk about that.

13:29

And that's the key point.

13:30

It's bone marrow, not cortical bone.

13:33

And basically, what does that mean?

13:35

That if you have radiographs that show metastatic

13:38

disease, that there is periosteal reaction, bony

13:41

destruction, metaphyseal lucent bands, then

13:44

that's considered stage M, not MS, regardless of

13:48

the age and the other findings. The radiographs,

13:51

the CT, and the bone scan should be normal.

13:55

It would be an MIBG scan that would show

13:57

you the marrow disease or a marrow biopsy.

14:01

The other thing that's been added to the new system

14:04

is what's called IDRFs or image-defined risk factors.

14:07

And you can see them listed here.

14:09

And basically what they talk about is

14:11

mass effect, vascular encasement, vascular

14:14

invasion, and other invasion of adjacent organs.

14:17

So, for example, if you invade the diaphragm,

14:20

uh, and we recently had a case like that.

14:23

So again, you look for these image-defined risk

14:25

factors, and those risk factors pertain toward the

14:28

ultimate staging, as well as the treatment protocols.

14:33

So you need to look for all these things.

14:35

And there are some great review

14:37

papers that talk about that.

14:39

Now, for the imaging, if you do have radiographs,

14:42

about half of neuroblastomas will demonstrate

14:45

some calcification. It may be hard to see, but if

14:48

you see calcifications, you're much more likely

14:50

dealing with neuroblastoma than Wilms tumor,

14:52

right off the bat by statistics.

14:55

Ultrasound, as we said, is usually the first

14:57

step. We favor MRI because neuroblastoma, neural

15:01

crest-derived tumors, neurogenic tumors, like

15:04

to be paraspinal and go into the spinal canal.

15:07

And a great way to look for that is with MRI.

15:11

And then again, our molecular imaging, nuclear

15:14

medicine workhorse is going to be MIBG, although

15:17

there is also PET and PET/CT imaging that is done.

15:21

So, for example, we look at this radiograph and I

15:23

already see a couple of things that make me concerned.

15:26

Number one would be that calcification

15:29

in the left upper quadrant.

15:30

I can see sort of clump-like calcification.

15:32

The other thing is the appearance

15:33

of the bony structures.

15:34

If you look at the iliac wings and the proximal femurs,

15:38

and even the ischium, they are very patchy and mottled.

15:42

There are some lucent areas that are

15:43

concerning for bony metastatic disease.

15:46

We may even have some loss of

15:47

height of this vertebral body.

15:50

We further look at this patient, and on a

15:51

sagittal left upper quadrant ultrasound, we

15:54

can see the splenic tip and a large suprarenal

15:57

mass with associated echogenicity centrally.

16:00

That represents the calcifications.

16:03

A little bit of shadowing here. On this patient's MRI,

16:08

we can see that there's an adrenal

16:09

mass, heterogeneous on T1,

16:12

mostly isointense to muscle, but with some bright

16:15

foci related to hemorrhage or mineralization.

16:18

Heterogeneous enhancement

16:20

above the kidney with mass effect. And MRI is

16:23

beautiful not only to show you the spinal

16:25

canal — you'll see that — but also for metastatic

16:28

lesions throughout the visible skeleton.

16:32

As I would point out in this slightly older

16:34

child, the marrow, even on T1, should not be so

16:37

dark uniformly. There should be more fatty marrow.

16:39

So as you learn marrow maturation processes

16:43

with age, you'll be able to quickly recognize

16:46

that this marrow is diffusely abnormal.

16:48

You see more focal enhancing rim-like

16:50

metastatic lesions, but actually almost

16:53

all of the marrow spaces are involved.

16:57

And in the same patient,

16:58

we can see this renal mass — mass effect on the kidney.

17:02

And I want to point out how it is encasing,

17:05

as we talked about with the IDRFs, the left renal

17:08

artery. There is mass effect on other structures.

17:11

And again, you get a beautiful

17:12

look at the spinal canal.

17:15

So, tip number two:

17:17

I love paraspinal lines.

17:19

I think that this is a great thing.

17:21

So, when you have a patient who they suspect

17:24

maybe has a mass or, um, you're even just reading

17:28

the chest radiographs for another reason,

17:30

I always like to look at my mediastinal lines, which

17:33

I'm sure you've learned about in other lectures.

17:36

Uh, if we look very carefully here, we

17:38

have the right heart border, but we have

17:39

additional densities that we can see — right

17:43

paraspinal.

17:44

There's also some fullness in the upper

17:46

abdomen. Would be hard to call on a

17:47

radiograph, but I will point that out.

17:50

So, if we look very carefully, we have

17:52

this line and we also have this line,

17:55

and you'll see another example coming up.

17:58

Neuroblastoma can be within the chest, can be

18:01

thoracoabdominal, can be within the abdomen.

18:04

I've seen many cases where it likes to crawl and move,

18:08

uh, retrocrural and then up into the middle and

18:11

posterior mediastinum, paraspinal in location.

18:14

On the ultrasound of this patient, we can

18:16

actually see the aorta encased by tumor.

18:18

Here's the spine, left lobe liver, right

18:22

lobe liver, and this is all retrocrural tumor.

18:24

This is actually all retrocrural tumor

18:26

with some calcification extending

18:29

up into the posterior mediastinum.

18:31

Now we look at it on MRI, and we can see how the crus

18:35

is elevated, so we understand why that paraspinal

18:38

line is abnormal. And we clearly see tumor extending

18:41

into the neural foramen and into the spinal canal.

18:47

So, if we use our tip, we take a look at

18:50

this and we say, well, there's just a lot of

18:51

fullness in the abdomen, but what—what's this?

18:55

I don't like this.

18:56

You know, that's not a normal

18:58

paraspinal line for just the descending thoracic

19:00

aorta coming to the thoracoabdominal aorta.

19:03

If we look very carefully, we also

19:06

have a little bit of calcification.

19:10

And again, we have a very large retroperitoneal mass.

19:13

We see not only encasement and elevation of

19:16

the aorta off of the spine, encasement of the

19:19

renal artery, the right renal artery, mass effect

19:22

on the kidney such that there is an obstructed

19:25

nephrogram compared to the normal left kidney.

19:27

We see how we cross midline, and as that tumor

19:30

extended superiorly, that's what gave us that

19:32

wide and left paraspinal line—from retrocrural

19:35

metastatic adenopathy or extension of tumor directly.

19:39

I will point out that neuroblastoma can present

19:43

with hypertension. And you can imagine why, based

19:46

on the sort of created renal artery stenosis and

19:50

or a paraneoplastic process from the tumor itself.

19:55

So here's the next tip: encasement of vessels.

19:59

If you see elevation of the aorta off the

20:01

spine and encasement of the aorta and other

20:04

great vessels, then think about neuroblastoma.

20:07

It likes to do that.

20:09

Lymphoma is on that same differential,

20:11

and you'll see examples later on.

20:13

Same is true with rhabdomyosarcoma

20:14

and germ cell tumors.

20:16

But in terms of—if we see this—what are the ones

20:20

that are gonna be more common in the abdomen?

20:22

We're really gonna think about these two.

20:24

And in the right age group: neuroblastoma.

20:29

Another patient who has a large suprarenal

20:32

mass on the left, already has metastatic

20:36

disease based on the T2-weighted MRI.

20:39

And we can see the encasement of the celiac trunk.

20:42

We see encasement of the descending thoracic—

20:44

I'm sorry, uh, abdominal aorta,

20:47

and again, this large abdominal mass.

20:50

Again, encasement of the aorta—not as

20:52

elevated, but encasement of some of

20:54

the branch vessels such as the SMA.

20:59

Now, I had mentioned to you that previous stage 4S,

21:02

or stage MS in the current system—neuroblastoma—

21:08

this patient looks quite abnormal right now.

21:11

This patient is under a year of age.

21:13

They have extensive metastatic

21:15

disease throughout their liver.

21:17

Look at the multiple metastatic lesions

21:19

throughout the inferior right lobe. And they have

21:21

a primary retroperitoneal tumor with some

21:23

encasement of the superior mesenteric artery.

21:27

So, when we take a look at this patient—

21:29

and a lot of mass effect elsewhere

21:30

too—we would say this looks terrible.

21:32

But again, MS does potentially have a better

21:35

prognosis. But you need to complete the evaluation.

21:38

So, do they have skin lesions? That’s still okay

21:41

for MS staging. But this is a different patient.

21:46

But if they had this bone scan, they could

21:48

no longer be MS. Because on this bone

21:51

scan, we see extensive metastatic disease.

21:54

We see it in the proximal femurs.

21:56

We see it throughout the spine, in the ribs.

21:58

We see it in the calvarium.

22:00

And in this particular patient—not germane to

22:02

this talk—but they actually had involvement

22:06

of the skull with extension of tumor into the

22:08

subcutaneous tissues and had a palpable mass.

22:11

So again, we would look at this bone scan,

22:14

this MDP bone scan, and say very abnormal. We

22:16

can actually see uptake by the primary tumor.

22:20

Now, in general, in younger children, looking for

22:23

metastatic disease—especially in neuroblastoma—

22:26

can be difficult on bone scintigraphy because

22:29

the metaphyses and the physes are quite active and

22:32

therefore have significant uptake of radiotracer.

22:35

The issue is how much is too much, and can you

22:39

truly tell? And it takes some experience as

22:42

to whether or not there's metastatic disease

22:44

within the ends of the long bones and metaphyses.

22:48

Metastatic disease—that's not uncommon.

22:50

That's a good place for

22:51

metastatic disease to set up shop.

22:54

So in this case, if our MS patient

22:57

had this bone scan, they would no longer be MS,

22:59

but be M. However, if their bone scan was normal

23:03

and they had just an MIBG scan—meta-iodobenzylguanidine,

23:09

a norepinephrine analog that is used for

23:12

imaging with typically Iodine-123—then you

23:17

would say that this could still potentially fit.

23:19

There is discussion about how much marrow

23:21

involvement is too much, and then you have

23:24

to treat them more as stage M versus MS.

23:27

But again, we can see the bony involvement.

23:29

We shouldn't have this kind of uptake

23:30

on MIBG. Uh, topic for another day.

23:34

But again, for MS disease, you can have

23:37

MIBG scan positive, but you should have

23:40

bone scan negative if you've done both.

23:45

So let's move on to Wilms tumor.

23:47

It's the most common solid

23:49

mass that we see in childhood.

23:50

As the children get a little bit older, the peak’s

23:52

a little bit older than for neuroblastoma, and they

23:56

can present with hematuria, high blood pressure,

24:00

especially they will present with significant

24:02

symptoms out of proportion to potential minor trauma.

24:05

That happens with a lot of renal lesions.

24:07

As a matter of fact, about 1% of

24:10

cases are familial, and we do know that

24:13

there are some associations that we

24:14

do a lot of screening ultrasound for.

24:17

So patients who have diagnosed congenital

24:20

hemihypertrophy or Beckwith-Wiedemann

24:22

syndrome, we will do routine ultrasound

24:25

screening, looking for the potential of Wilms

24:27

tumor as well as some other tumors as well.

24:29

But especially Wilms tumor. Aniridia with a

24:33

particular deletion is another risk factor.

24:35

Now in that case, this is not familial

24:38

aniridia, but typically sporadic aniridia.

24:40

And the aniridia is part of the mnemonic for

24:44

WAGR syndrome, Dennis-Drash syndrome.

24:47

There are some associations with Perlman and

24:51

neurofibromatosis, but the ones I want you to

24:53

remember are: if you know the patient has these three,

24:57

that’s an important association for Wilms tumor.

25:00

And I'm sure with advancements in our

25:02

genetic understanding of disease, we may

25:04

even find more. If it's bilateral synchronous,

25:09

that's technically stage five Wilms tumor.

25:11

That usually occurs in much

25:15

younger patients and will have underlying

25:18

problems with either nephroblastomatosis

25:21

or at least nephrogenic rests.

25:24

Now, Wilms tumor staging, as I said, it's

25:27

a more typical staging—except for stage

25:29

five, which is bilateral synchronous Wilms.

25:33

On imaging, we said that you can have calcification,

25:36

but you usually don't see it on radiograph.

25:38

It's very subtle.

25:40

And it's not that common.

25:42

What we are looking for is vascular thrombosis.

25:44

I should have put this in a highlight

25:46

because that's such an important part

25:48

of the evaluation of Wilms tumor.

25:49

And then we do know that up to a fifth to a

25:52

quarter of patients will have pulmonary metastases.

25:56

So there is a debate about MRI or CT because

26:00

CT is so great for the pulmonary metastases.

26:03

Should you just continue and do the

26:04

imaging of the abdomen and pelvis

26:06

as well for staging or go on to MRI?

26:10

Again, it depends on the situation.

26:12

If I have an old enough patient who can

26:13

cooperate with MRI without sedation, I

26:16

would potentially do CT of the chest and

26:18

then just move them over to the MRI suite

26:20

and perform an MRI of the abdomen and pelvis.

26:24

So here's a CT of a large Wilms tumor.

26:26

As you can see, this tumor, instead of

26:28

encasing the aorta, is displacing it.

26:31

And the IVC over to the right. We also see

26:34

a little bit of enhancing renal parenchyma.

26:36

We look for this claw sign

26:38

to tell us that this was a renal mass that

26:40

has broken out into the retroperitoneum.

26:45

Uh, regional adenopathy can be seen.

26:47

This is the MRI of this patient.

26:49

Okay.

26:50

We can also look for liver metastases,

26:52

and again, CT for pulmonary metastases.

26:57

Another patient with a very large Wilms tumor, and

27:01

again, we can see that claw. We can look at the liver.

27:05

Typically, Wilms tumor does not go to bone, so the

27:08

MRI doesn't give you necessarily that advantage.

27:10

If you do see bone lesions, you start to think

27:13

about another diagnosis. And you can pick up larger

27:16

lesions, but not necessarily the smaller ones.

27:20

This patient, which I had quite some time

27:23

ago, has a very nice ultrasound example

27:26

of one of the problems with Wilms tumor,

27:28

which is it likes to have vascular invasion.

27:31

If we look down to the CT, we can see the claw sign.

27:34

And the large heterogeneous mass

27:35

on CT for this Wilms tumor.

27:38

And we can actually see tumor thrombus extending

27:40

in the left renal vein over to the IVC in this

27:43

particular patient on a different patient.

27:46

This is a sagittal image.

27:47

Here is the right hemidiaphragm, hepatic vein, liver.

27:51

We can see the right atrium a little bit.

27:53

This is the IVC completely filled with tumor thrombus

27:57

extending all the way up into the right atrium.

28:00

In this particular case.

28:01

Here is the aorta on a transverse image.

28:03

This is the IVC and actually that, that, uh,

28:08

lit up with color Doppler. That is neovascular

28:11

of the tumor thrombus going up into the IVC.

28:14

That's one of the ways that you can try and

28:16

tell the difference between bland thrombus, uh,

28:19

versus tumor thrombus, is if there is actually

28:21

blood flow within the, the, uh, thrombus

28:24

that you see on this MRI. A Wilms tumor on the

28:27

left, left renal vein extending up the IVC.

28:33

As I mentioned, stage five Wilms tumor

28:36

will show you bilateral renal masses.

28:39

And so we have that in this particular patient.

28:41

You do have to wonder about underlying

28:43

nephrogenic rests, precursors to Wilms tumor, um,

28:47

and, uh, also certain genetic predispositions

28:51

that might lead to bilateral Wilms.

28:54

Again, you can look at the liver, but liver metastases

28:57

are not that common in classic Wilms tumor as

29:01

compared to lung metastases, which you can pick

29:03

up larger lesions on MRI within the lung bases.

29:07

Again, the mediastinal spaces are usually normal.

29:09

Again, the important part is to make sure that

29:12

you look for the multiplicity, the extent of

29:15

the lesion, you're descriptive in terms of its

29:17

enhancement pattern and enhances heterogeneously.

29:20

Wilms can be quite cystic as well, uh,

29:23

and you're especially looking for that

29:24

vascular invasion like I showed you.

29:28

Uh, another entity that you can on, uh, uh,

29:32

uncover on occasion is the either focal nephroblastomatosis,

29:37

or in this case diffuse nephroblastomatosis.

29:38

Nephroblastomatosis.

29:40

So we actually have a T1-weighted image here

29:42

and a post-gadolinium T1-weighted here.

29:44

It was not done with, uh, fat saturation, but

29:47

we can see that all these lesions are enhancing

29:50

and they are peripheral in location with some

29:53

centrally spared renal parenchyma, bilateral

29:56

nephromegaly in this very young patient.

29:58

And this is diffuse nephroblastomatosis

30:00

where if you biopsy these, they

30:03

would be precursors to Wilms tumor.

30:05

They would be large nephrogenic rests.

30:08

Uh, and you have to follow these

30:10

patients very carefully, uh, because

30:13

any of these can turn into Wilms tumor.

30:18

Now what about other renal neoplasms we might see?

30:22

I mentioned if you have a renal mass and you

30:24

think you see bone lesions, that's not a common

30:28

occurrence for Wilms tumor. Anaplastic Wilms tumor,

30:31

very aggressive Wilms tumors, not the classic triphasic

30:34

Wilms tumor, can do a lot of very unusual things.

30:37

But if I see bone lesions, I start to think

30:40

about what we used to call many years ago

30:42

Wilms variants, now separated out as other tumors,

30:46

including the one that likes to go to bone or

30:48

can, called clear cell sarcoma of the kidney.

30:52

Its imaging is gonna be very similar to

30:54

what a Wilms tumor would do, but again, the

30:56

bone metastases does favor that diagnosis.

30:59

At other times, they only will

31:00

know at the time of pathology.

31:03

The rhabdoid tumor of the kidney is in much younger patients.

31:07

It's a very aggressive tumor.

31:08

It's almost in the same family

31:10

as, uh, atypical teratoid/rhabdoid tumor.

31:13

And, uh, their hallmark is that you can have

31:16

brain lesions, especially posterior fossa.

31:19

And there is some debate about whether or not

31:21

it is a second primary of rhabdoid tumor or

31:24

an ATRT, um, type lesion versus metastatic

31:29

lesion from the primary in the kidney.

31:32

We do see renal cell carcinoma.

31:34

It's rare, it's, uh, older children,

31:38

but we do see it on occasion.

31:40

There's a rare entity called renal medullary

31:42

carcinoma, which I do want to point out because if

31:45

you're working at a larger center with sickle cell

31:47

patients, this is one that they are at risk

31:51

for, although it's still a very rare diagnosis.

31:54

So especially in sickle cell trait. I've also

31:56

seen it in sickle cell heterozygous SC disease.

32:00

And then finally, you can uncover

32:02

renal lymphomas and leukemias.

32:06

Now this is a CT example.

32:08

I do not have an MRI example of renal medullary

32:10

carcinoma in a patient with sickle cell trait.

32:13

Uh, and I would like to thank the Society

32:14

for Pediatric Radiology for this image.

32:17

Um, so we see a renal mass and

32:20

we also see extensive adenopathy.

32:22

Now we could add renal medullary

32:24

carcinoma, another very aggressive tumor,

32:27

to the encasement of the aorta category.

32:29

Although it's such a rare tumor, I

32:31

don't usually include it on my list.

32:33

But again, this is renal medullary carcinoma.

32:35

Very aggressive, very poor prognosis.

32:39

And this patient was a very interesting patient who

32:42

had had multiple surgeries for scoliosis and had

32:46

developed what was believed to be osteomyelitis of the

32:48

hardware and the spine, and had the hardware removed.

32:51

And you can see postoperative changes

32:54

as well as abnormal soft tissue.

32:56

But what we also uncovered at the time were bilateral

32:59

renal masses when we were doing their spine imaging,

33:01

which this would be very similar to what we would

33:03

do for abdominal imaging with MRI for tumor.

33:06

And these bilateral renal masses

33:08

turned out to be Burkitt lymphoma.

33:11

So again, lymphoma can give you multiple masses.

33:17

Turning to liver tumors.

33:19

Liver tumors are, um, gonna be, there's

33:23

gonna be some overlap with, uh, many of

33:25

the tumors with regards to how they image.

33:28

And it's a different discussion that we

33:29

would have with regards to whether or

33:32

not you would use a hepatobiliary agent,

33:35

gadolinium hepatobiliary agent,

33:37

as compared to more traditional

33:40

gadolinium, uh, contrast.

33:42

Uh, and again, that would be a topic for another

33:44

time, but, uh, they do have a lot of overlap.

33:48

There's certain ones that I do wanna point

33:49

out though that might be helpful to you.

33:52

And one of the things with liver

33:53

tumors is that the age is very helpful.

33:56

So there's certain tumors that we,

33:58

you typically see in the very young,

34:00

as you can see listed in this chart.

34:02

And when we get to be in the teenage years,

34:04

we start to think about other tumors as well.

34:07

And so knowing the patient's

34:08

age can be very, very helpful.

34:14

Uh, again, uh, uh, image that, uh, I borrowed from,

34:18

uh, Radiographics and Dr. Chung from their excellent,

34:21

uh, article as referenced below. You can see, uh, in

34:26

mesenchymal hamartoma in a very young patient here.

34:28

They've done MRI, the asterisks are showing

34:30

you normal liver, and we have a very bright

34:33

T2-weighted image within the liver that

34:36

has multiple septations and cystic spaces.

34:39

Uh, on a contrast-enhanced image,

34:41

the septations would enhance.

34:43

The cystic components would not.

34:45

We recently had a patient that had CT imaging that

34:48

showed a very, very similar-like lesion, cystic

34:52

with septal enhancement, thin and perceptible wall.

34:55

And you can tell it's a very, very

34:57

young child, just several months old.

34:59

And this was a mesenchymal hamartoma

35:01

at pathologic diagnosis.

35:03

So again, uh, cystic, they can

35:06

be solid, but cystic and, um, uh,

35:15

young patient, uh, very, very

35:18

little solid enhancing components.

35:19

These are all the things that you want to think about

35:21

with mesenchymal hamartoma as a potential liver lesion.

35:25

The next one I want to talk about is

35:27

hemangioma and hemangioendothelioma.

35:29

Those are hard to differentiate routinely

35:32

by imaging, uh, but we're mostly talking

35:34

about the infantile hemangioma.

35:37

So it's a benign endothelial proliferation.

35:41

It can lead to a lot of shunting.

35:42

It's a very vascular neoplasm.

35:45

Uh, patients can present with

35:46

congestive heart failure.

35:48

As a matter of fact, uh, as a pediatrician,

35:51

um, if you were seeing a patient and they

35:53

were in congestive failure, you would, um,

35:57

listen over the heart for a potential shunt.

36:00

You would listen to the lungs.

36:02

You would listen to the anterior fontanel, listening

36:05

for a potential vein of Galen malformation, which can

36:07

lead to, uh, shunting and congestive heart failure.

36:11

But you would also listen over the

36:12

liver, looking for the potential of a

36:14

bruit and potential liver lesions, such

36:16

as hemangioma or a large hemangioendothelioma.

36:19

It proliferates, and then involutes.

36:23

You can have anemia and jaundice.

36:25

There is an association with hypothyroidism as well.

36:29

Um, and then there is a particular syndrome called

36:32

the Kasabach-Merritt syndrome, where you can have

36:34

loss of platelets, uh, consumptive coagulopathy.

36:38

The treatment currently is at times just observation,

36:42

depending on the clinical scenario, 'cause they

36:44

should involute all or, alternatively, uh, medications

36:47

such as propranolol, a beta blocker, or steroids.

36:51

These can be embolized as well,

36:52

since they're highly vascular.

36:54

So in this particular patient, we see

36:56

the bowel is displaced inferiorly.

36:58

We have either a large mass or hepatomegaly.

37:02

Uh, heart is a little bit big.

37:03

We do not have gross congestive heart failure.

37:05

However, when we do an ultrasound of the abdomen,

37:09

we see multiple hypoechoic lesions that are quite

37:13

vascular, flow within them, flow around them.

37:16

There's a lot of vascularity to this liver that

37:18

we would not typically see on color Doppler.

37:20

And again, look at the lesions and the

37:23

size of the liver compared to the kidney.

37:25

This is the right kidney.

37:28

We do MRI.

37:29

These lesions are typically hyperintense

37:31

on T1, hyperintense on T2, and

37:34

this is another T2-weighted image.

37:36

Um, and again, they should show

37:39

enhancement because of their vascularity.

37:42

And again, we can see the hepatomegaly.

37:44

And this particular patient had multiple hemangiomas.

37:49

So the next tip, if you see multiple liver

37:52

masses in the neonate or young infant, um, this

37:56

is the list that I want you to think about.

37:59

So you wanna take a look at that vascularity, and

38:01

I'm gonna talk about that with another tip coming up.

38:03

You to think about hemangioma

38:06

or hemangioendothelioma.

38:08

Metastatic neuroblastoma.

38:09

I already showed you multiple liver lesions.

38:11

They can be large, they can

38:12

be small, variable in size.

38:15

And then there's also, uh, multifocal hepatoblastoma.

38:18

Uh, now typically hepatoblastoma is not multifocal.

38:22

That's not the routine presentation, so

38:24

you would put that lower on your list.

38:25

And again, if the patient is acting infected,

38:29

uh, then potentially multiple abscesses, and

38:32

abscesses can occur in association in the neonate,

38:34

for example, with umbilical venous catheters.

38:39

So the next tip, the tapering of the aorta

38:42

with shunting in the patients who have

38:43

multiple hemangios within the liver.

38:47

There is a lot of shunting.

38:48

Look at, for example, on this CT, here's a large,

38:52

uh, giant hemangioma within the liver in this

38:54

neonate, uh, uh, again, another borrowed image.

38:57

And we can see the size of the hepatic artery,

39:00

the proper hepatic artery, and the celiac

39:02

trunk with the takeoff of the splenic artery.

39:04

Because of all this shunting, and look at the neo-

39:07

vascularity, the, uh, proper hepatic artery is almost

39:10

the same size as the aorta in this same patient.

39:13

We look down, we can see how

39:14

it's starting to taper even the—

39:16

The celiac trunk is much bigger

39:19

than the superior mesenteric artery.

39:21

And again, the blush of that hemangioma.

39:24

Again, you can see the same thing on Doppler

39:26

with very, uh, fast, low-resistance flow.

39:30

Again.

39:31

Um, again, the resistive index here is only 0.5,

39:35

and again, we can see the tapering of the aorta

39:37

after the takeoff of the celiac trunk, which

39:39

is where the shunting will occur for the AV

39:41

shunting of hemangios and hemangioendotheliomas.

39:46

So look for that. That can be a helpful

39:48

sign — that vascularity. Hepatoblastoma,

39:51

the other lesion that you would

39:52

be thinking about is typically

39:55

not as vascular as that.

39:57

So that can be helpful, uh, especially

39:59

if you have one large giant angio.

40:01

The other thing that will help

40:03

will also be clinical scenario.

40:04

So are there risk factors?

40:06

What is the alpha-fetoprotein level?

40:08

Those kinds of things.

40:10

So in hepatoblastoma, we said there

40:11

was a young patient — that was on our

40:13

original chart — more common in boys.

40:17

And the risk factors, I've listed several here.

40:20

It also is congenital hemi-

40:22

hypertrophy and Beckwith-Wiedemann.

40:23

So we already mentioned before that we do screening

40:26

with ultrasound for tumors in those patients.

40:29

That would also include hepatoblastoma.

40:31

Uh, FAP is another one.

40:34

And then I want to point out that prematurity,

40:36

especially in very low birth weight infants,

40:38

there is an association, um, not a hundred

40:42

percent sure why, with hepatoblastoma.

40:46

The easy answer to this, if it ever shows

40:48

up on the test, it's more commonly found in

40:49

the right lobe liver, and that's because the

40:51

right lobe liver is—the right lobe is—bigger.

40:54

Um, there are different, uh, subtypes of

40:56

hepatoblastoma with prognostic implications.

40:59

Again, you need to look for an

41:00

elevated alpha-fetoprotein.

41:03

And in the same vein as with Wilms tumor,

41:06

hepatoblastoma does metastasize to the lungs, and

41:09

you really do need to know about pulmonary nodules.

41:12

And so therefore, do you do the CT,

41:14

chest, abdomen, pelvis all in one stop,

41:17

or do you move on to MRI? And it varies.

41:20

Again, it depends on a lot of

41:22

the factors that we talked about.

41:24

Ultrasound is still gonna tell you that its

41:26

organ of origin is the liver, and then you

41:29

can start working the patient up from there.

41:31

You do need to take out everything in order to have

41:35

a potential cure.

41:36

Uh, I don't wanna spend a lot of time. We could

41:38

spend a lot of time talking about hepatoblastoma

41:40

and the new way that we use to really, uh, try and

41:44

stage the hepatoblastoma at the time of diagnosis.

41:48

There's something called a PRETEXT classification,

41:51

which I haven't mentioned here, but I

41:53

think is an important thing to look up if

41:54

you do have a patient with hepatoblastoma.

41:57

So a large liver mass, potentially some calcifications,

42:02

here, not vascular like we saw with a giant angio.

42:07

And again, it's very heterogeneous on T2,

42:11

and it has heterogeneous enhancement here.

42:13

It has almost the appearance of a central-type

42:15

scar, and it can. So the central scar is not

42:18

unique to just FNH or fibrolamellar variant of HCC.

42:24

And again, look at the age of the patient.

42:26

You can tell just by looking at the

42:27

MRI. Here's another one that has a bit

42:30

more of a central scar appearance to it.

42:32

Very innocuous looking.

42:33

Very exophytic off of the right lobe liver.

42:36

Another patient with hepatoblastoma.

42:41

How about hepatocellular carcinoma for liver lesions?

42:45

Well, in most cases it will be chronic liver disease.

42:48

So we do a lot of screening.

42:50

Um,

42:52

we do a lot of screening, um, for patients

42:58

for HCC if they have underlying chronic liver

43:01

disease, which includes Fontan hepatopathy.

43:03

I haven't listed that here as well, but that's

43:05

become much more of a common occurrence,

43:08

especially in our cardiac, uh, patients

43:12

who have undergone Fontan procedures.

43:14

Um, you do look for now elevated alpha-fetoprotein.

43:17

There is this teenager, uh, fibrolamellar variant.

43:20

It doesn't have to be a teenager.

43:21

Classically, it's older children, no

43:23

association with chronic liver disease.

43:25

Uh, and they will have a central

43:27

scar mimicking other lesions as well.

43:30

So again, the fibrolamellar

43:32

variant is a harder diagnosis to make.

43:35

Most of the time we're doing screening in the

43:37

chronic liver disease patients, and the ones

43:39

that we most commonly see would be cirrhosis for

43:42

various reasons, which would include patients

43:44

who have had prior Kasai procedure

43:46

for biliary atresia or neonatal hepatitis.

43:49

Uh, we do see occasionally glycogen storage

43:51

disease patients, and, uh, I've seen one

43:54

or two patients with tyrosinemia as well.

44:00

This is an example of a fibrolamellar variant of HCC.

44:03

Again, a very large heterogeneous

44:05

mass within the right lobe liver.

44:07

Um, we can see its relationship to the

44:09

vessels, and that becomes important,

44:11

uh, in the hepatoblastoma patients.

44:13

If this were hepatoblastoma, uh, looking at

44:16

various, uh, factors for that PRETEXT and POSTTEXT

44:20

classifications. And there

44:22

are very good papers on that

44:23

if you're interested. And again, this shows

44:25

us heterogeneous enhancement, maybe the

44:27

attempt of some type of a central scar.

44:29

You'd wanna look for early

44:31

enhancement of the central scar.

44:35

Let's move on to rhabdomyosarcoma.

44:38

So in, uh, rhabdomyosarcoma, uh, the three locations

44:42

it likes to occur in the pediatric population are

44:45

head and neck, genitourinary, and the extremities.

44:49

So again, it's another one of the sarcomas

44:52

of the extremities where we would be looking

44:53

for lung metastases, typically with CT.

44:56

Uh, but again, it can occur in the abdomen as well.

45:00

The classic locations are in the urinary

45:02

bladder, the vagina, and in the prostate.

45:07

Rhabdomyosarcoma can occur anywhere else

45:09

in the abdomen and has a predilection for

45:12

peritoneal spread of tumor, uh, as well.

45:15

And we'll talk a little bit about that.

45:17

But again, these are the three major sites

45:19

in the abdomen that we do think about.

45:21

So you think about rhabdomyosarcoma if you see

45:23

a bladder mass or if you think there's a mass

45:25

arising, uh, from the prostate or in the case

45:29

of the vagina, you can have something called

45:31

sarcoma botryoides, that cluster of grape

45:33

appearance to the mass that is visible on exam.

45:38

Um, rhabdomyosarcoma can also occur in the

45:40

biliary tree and its classic metastatic

45:44

pattern is to the lungs and to the bone.

45:50

So, uh, the next tip — look at the rectal gas pattern.

45:54

Now in this particular patient, we

45:56

really don't see much rectal gas.

45:58

We do see what looks like maybe a distended

46:01

urinary bladder, but not much rectal gas.

46:03

And I also try and take a look at the

46:05

levator internus fat planes as well.

46:07

I have seen several cases of bladder

46:11

and, uh, prostatic rhabdomyosarcoma.

46:14

I've also seen a case of prostatic lymphoma where

46:17

the rectal gas is displaced off to one side.

46:20

So I always like to make sure that if I see the

46:22

rectal gas, that it's nice and midline, and the fat

46:24

planes look symmetric to me, as best as I can tell.

46:27

That's a quick look, uh, to see if someone

46:30

has the potential, um, for a pelvic mass.

46:33

Uh, but again, if the rectal gas is off to

46:35

one side or the other, and I've seen that in

46:37

the case of vaginal rhabdomyosarcoma where

46:39

it was clearly evident on the radiograph.

46:41

And then when the physical exam was

46:43

finally completed, we found out there

46:45

was a protruding mass from the vagina.

46:47

So use that clue. And this patient is constipated,

46:51

was having, uh, signs of obstipation as

46:54

well, was having straining and difficulty

46:56

and pain with going to the bathroom.

46:58

So we did an ultrasound.

47:00

This is the urinary bladder, sagittal, head and feet.

47:03

And we can see this large heterogeneous

47:05

mass pushing on the gas-filled rectum.

47:08

The spine would be back here, and again,

47:11

we can understand why the rectal gas would

47:12

be displaced or effaced — urinary bladder,

47:18

the large mass, the rectum is displaced

47:21

over to the right, and again, we can

47:22

see how this is a very necrotic tumor.

47:25

This was a prostatic rhabdomyosarcoma.

47:29

Another patient with a prostatic

47:31

rhabdomyosarcoma.

47:32

They have cystic change with hemorrhage into the mass.

47:35

This is the Foley catheter, which is encased

47:38

and displaced by the mass, which makes

47:41

sense considering its prostatic in origin.

47:44

And we already can see that there are bone

47:47

lesions consistent with bony metastatic disease.

47:51

Also metastatic adenopathy within

47:54

the right iliac, uh, chain.

48:00

So.

48:00

Another tip — omental caking or

48:02

peritoneal seeding of tumor.

48:04

So for example, on this CT, I did not

48:06

have an example on MRI, but you would look

48:08

for the same thing — enhancing tumor.

48:10

And I will give you another little tip off of this,

48:13

but this is all tumor, and we can see the thick

48:16

nodular enhancement of the peritoneum next to the

48:19

right kidney, and a little bit along here, and along

48:23

the falciform ligament and throughout the mesentery.

48:26

And so this omental caking or peritoneal

48:28

seeding — this peritoneal carcinomatosis, in

48:31

essence — the differential diagnosis

48:36

that we think about is rhabdomyosarcoma, Burkitt

48:39

type lymphoma especially, and any lymphoma.

48:42

And then ovarian neoplasms as well, which

48:45

we're — we're gonna leave for another day.

48:50

So let's finish up with lymphoma.

48:52

Okay.

48:53

Multiple presentations.

48:54

I'm sure everybody's very familiar

48:55

about mediastinal masses and adenopathy.

48:58

I will talk about a couple of things that we do

49:00

think about with lymphoma — especially the vessel

49:03

encasement, and the potential for its being the

49:06

pathologic lead point of an ileocolic intussusception.

49:10

It also could be other types of

49:11

intussusception, including colocolic.

49:14

So, uh, borrowed images to show you an intussusception

49:17

related to Burkitt lymphoma. We can see tumor within

49:20

the liver, multiple masses within the left kidney,

49:26

also within the right kidney, barely visible.

49:28

This is a different patient.

49:30

The encasement of the vessels — look at

49:31

the celiac trunk, proper hepatic, and

49:34

the splenic artery all encased by tumor.

49:37

And here we have bilateral ovarian involvement

49:40

and peritoneal seeding and omental caking.

49:45

And these were all cases of Burkitt lymphoma.

49:50

In this particular patient, I think that many people

49:53

are aware of the fact that it can involve the bowel.

49:55

I've seen it, um, involve the, uh,

49:57

rectum with a very similar appearance.

50:00

I did not have an MRI example.

50:02

In this example from Dr. Chung, we can

50:04

see that the bowel wall is thick and

50:07

the bowel loop itself is aneurysmal.

50:09

Then we can see an air-fluid level within

50:11

the bowel, and it's pointing to you

50:13

the very thick, abnormal loop of bowel.

50:16

So when you see that, an aneurysmal change in bowel

50:19

wall thickening, one of the things to think about,

50:22

and almost always to think about in pediatrics, is

50:25

lymphoma and lymphoma involvement of bowel.

50:31

So what other takeaways from

50:32

what we talked about today?

50:34

So the first thing is think common tumors first.

50:37

So we know that the most common ones we

50:39

see are neuroblastoma and Wilms tumor.

50:42

We mentioned a couple of other things, including

50:44

lymphoma in the slightly older patients.

50:46

If you see encasement of vessels, an elevation

50:49

of vessels like the aorta off of the spine,

50:51

think about neuroblastoma, lymphoma, and rhabdo-

50:54

myosarcoma can also do that if it's going

50:57

into the neuroforamina or the spinal canal.

50:59

Neurogenic tumors and neuroblastoma,

51:02

until proven otherwise.

51:03

We didn't go into the neuroblastoma–

51:06

to–ganglioneuroma spectrum.

51:08

There's ganglioneuroblastoma and ganglioneuroma,

51:11

uh, and those are just more mature neurogenic tumors.

51:14

Uh, but I wanted to concentrate

51:15

mostly on neuroblastoma.

51:17

If you see bilateral renal involvement, it can be

51:20

bilateral Wilms, so you have to think about that.

51:23

But leukemia and lymphoma can do it as well.

51:26

Lymphoma — if you see intussusception out of

51:29

the normal typical age range for ileocolic

51:32

intussusception, and ultrasound shows you a

51:34

potential mass as a pathologic lead point,

51:36

think about Burkitt-type lymphoma.

51:38

I've seen this now maybe about a

51:39

half dozen times in my career as the

51:41

presentation of their Burkitt lymphoma.

51:44

Uh, and then liver tumors — the age is important.

51:47

Use that vascularity like we talked

51:48

about for hemangioma, giant hemangioma.

51:51

Obviously, if it's multiple lesions, you'll even

51:53

more likely favor the potential of hemangioma.

51:56

And then remember that rhabdomyosarcoma likes

51:59

to go to three specific places — to the head and

52:01

neck, which we weren't gonna talk about today,

52:04

but genitourinary is very important.

52:06

And again, it can also be in the extremities —

52:08

one of its more typical presentations.

52:11

And I think that's everything.

52:14

So what I'm gonna do is I'm

52:17

going to now go to the Q and A.

52:21

Um.

52:23

And so, uh, I'm gonna try and, uh, answer those

52:26

questions, and I hope everybody can, uh, hear me.

52:29

So, uh, Alan asked, what is the most common

52:31

presentation of large B-cell lymphoma in children?

52:35

Uh, my experience — I don't know the textbook answer.

52:39

My experience has been mostly for mediastinal

52:41

mass and, uh, lymphoblastic lymphoma especially.

52:45

Uh, one of the more, uh, typical presentations

52:48

would be with pericardial and pleural effusion

52:50

associated with that mediastinal mass.

52:52

That's what I have seen.

52:54

Um, and at what age — Alan also asked — so what

52:57

age do you stop screening for Beckwith-Wiedemann?

53:00

Um, that's an interesting question.

53:03

Um, so, uh, there's not great

53:07

literature about when you stop.

53:09

There's not even a lot of consensus.

53:11

When you look at the literature about

53:12

when to lengthen your screening.

53:14

So, uh, if a child is born and a diagnosis of Beck-

53:18

with-Wiedemann is made, they're screened every three

53:20

months with ultrasound, usually up till about three to

53:24

five years of age. Then it goes to every six months.

53:27

But I've seen some doctors continue with

53:29

every three months up to teenage, and then

53:31

I've seen people usually stop at age 10.

53:33

I've seen other people go up to age 15.

53:36

I'd have to go back and look at the more common,

53:38

um, cutoff points and the more recent literature.

53:41

But usually the screening stops as you start

53:44

to get into the teenage years, although we

53:45

still have some teenagers that we follow.

53:48

So there's not a, there's not a perfect answer there

53:50

in terms of what the referring physicians are doing.

53:54

Okay.

53:55

Let me see if there's anything else I can... Um, what's

54:00

our protocol for follow-up of nephrogenic rests?

54:02

I happen to like MRI, and we

54:06

usually do renal mass protocol MRI.

54:08

Um, and the reason is, is that the signal intensity

54:12

might be able to tell you a little bit about whether

54:15

or not it is hyperplastic or fibrotic, which

54:19

might give you a little bit more information.

54:21

In general, any imaging should be fine, 'cause

54:24

it's really gonna be about size change and

54:26

aggressiveness of any rest you do, uh, see

54:30

as to whether or not you're gonna start to

54:31

worry about the potential of a Wilms tumor.

54:33

So if it starts to rapidly enlarge, um, if it

54:36

starts to become more cystic, if you see any

54:39

new adenopathy, then obviously you start to get

54:42

more concerned that it's a developing Wilms.

54:44

And the surgeons are usually pretty quick,

54:48

and the oncologists are pretty quick to, to, to do

54:50

something about that lesion before it becomes too big.

54:53

Because as it continues to enlarge, think about

54:55

it, if you have nephrogenic rests, i.e., you are

54:59

going to typically be multiple and bilateral.

55:01

You would like to do renal-sparing surgery.

55:03

So it becomes harder the larger the mass becomes.

55:05

So as soon as you start to have any type of concern,

55:09

usually pretty quickly go to, uh, either biopsy

55:13

or, uh, mass resection or partial nephrectomy.

55:17

Um, but I do like MRI, I think, because it is not only

55:21

a vascular phase agent, but a tissue phase agent.

55:25

You can usually get some very nice

55:27

imaging and really pick up the lesions

55:29

and make them a little more conspicuous.

55:31

With MRI, you're not beholden to the timing of the

55:34

bolus just with CT, depending on, you catch it in the

55:36

nephrographic versus the corticomedullary phase.

55:40

So it really depends.

55:41

Now again, timing with, um, bolus tracking

55:44

and so forth makes that easier, but

55:45

sometimes it doesn't work out perfectly.

55:48

Um, cystic, partially

55:49

differentiated nephroblastoma.

55:51

Do you use the same staging as Wilms tumor?

55:53

That's a great question.

55:54

I actually don't know the answer to that.

55:56

Um, uh, we have not had in several years, uh, the

56:01

CPDN, so, um, I don't know the answer to that.

56:06

I would think that we would probably use the same

56:09

staging system, but since it's felt to be sort of,

56:13

uh, in between a cystic nephroma and a Wilms tumor as

56:17

well, it's less likely to give you metastatic disease.

56:21

Um, but you still would look for regional adenopathy,

56:24

uh, uh, as well as part of your abdominal imaging.

56:27

Um, let's see here.

56:29

Do you use hepatic MRI contrast in differentiating

56:32

liver lesions at any pediatric age?

56:34

Can we apply LRAD in pediatric HCC?

56:38

So, uh, two great questions.

56:40

Uh, number one, we do use, uh, TATE

56:44

in, uh, liver, uh, tumor imaging.

56:47

We especially use it in our screening of our

56:49

chronic liver disease patients, such as the

56:51

Fontan patients and other patients with history

56:54

of, uh, primary sclerosing cholangitis

56:57

or other related, uh, uh, liver issues.

57:01

So, um, we do use it, we will

57:03

use it in almost any age group.

57:05

Um, we don't typically use it

57:08

under a year of age.

57:10

Um, but, um, it can be used, you know, and we

57:15

have not had the problem with the respiratory

57:18

distress that some people have talked about

57:20

with using some of these hepatobiliary agents.

57:23

So we do use it.

57:25

It's not usually the contrast of choice

57:28

at initial tumor imaging. We'll usually stick

57:31

with a more typical gadolinium agent,

57:34

because you can do wonderful things with that.

57:36

And especially if you're using multi-hance, you

57:39

would have the ability to capture some of the,

57:42

uh, hepatobiliary phase as well if you needed to,

57:44

uh, as compared to doing, for example, MRCP as

57:47

part of your liver tumor protocol as well.

57:51

And we could talk about that another time.

57:54

Can you apply LRADs?

57:56

Um, people have tried to look at this.

57:58

I would refer you to several articles from

58:00

Jonathan Dillman and from Andrew Trout from

58:04

Cincinnati Children's regarding that concept.

58:07

Uh, you can technically apply LRADs in the

58:11

teenager group, um, but it's not routinely used

58:15

by pediatric radiologists, is my understanding.

58:18

Let's see if there's any other questions.

58:21

Okay.

58:23

Um, which pediatric abdominal peritoneal

58:27

seeding do you see more commonly?

58:30

Um, the one that we see most commonly, I

58:32

would think is probably rhabdomyosarcoma.

58:35

I have seen a couple of cases where lymphoma has

58:38

uh, uh, done that as well.

58:40

I would like to point out, I didn't

58:41

mention this earlier, I think diffusion

58:43

weighted imaging is a great tool for this.

58:46

Um, and that's why we always do it as

58:47

part of our abdominal tumor imaging.

58:50

And most of our abdominal protocols

58:51

include, uh, included typically.

58:54

Um, and the reason is, is that it will show you

58:57

areas of restricted diffusion from subtle tumor

58:59

seeding that you might not otherwise pick up on

59:01

your T1 and T2-weighted images as you're

59:03

doing your, uh, routine scrolling and evaluation.

59:07

And so I see some areas that pop up and then

59:10

I can go back and take a look to see if there

59:12

is any subtle enhancement or nodularity that

59:15

might be concerning for peritoneal seeding.

59:18

Um, we had a boy who had an extrarenal Wilms

59:22

tumor who had a recurrence that was very, very

59:25

subtle that my partner expertly picked up.

59:28

Um, uh, by using the diffusion-weighted

59:31

imaging first and then going back to

59:33

be able to find the subtle seeding.

59:35

Uh, what are the sequences you must do

59:38

when imaging neuroblastoma and Wilms?

59:39

In MRI, do you use the full routine abdomen

59:42

MRI sequences, which can take a very long time?

59:44

And would you follow them with MRI?

59:47

So, um, we, uh, typically will do as I mentioned

59:51

on, on some of the earlier slides, just a,

59:54

um, T1, a T2 fat-saturated and post

59:58

Gad fat-saturated T1-weighted imaging,

60:00

usually in two planes.

60:01

I don't necessarily need the third plane

60:03

unless it'll answer a specific question.

60:06

Um, you can try and cut down some of the sequences.

60:09

Um,

60:12

it does take a lot of time.

60:14

We usually don't do multiplane.

60:16

On the pre-contrast, maybe it'll

60:19

only just be coronal T1.

60:21

That'll give us a beautiful view of the abdomen.

60:24

It'll show us the spine, it'll show us the

60:26

spinal canal, it'll show us the kidneys,

60:28

if we're dealing with a Wilms tumor.

60:30

And then we can go on to an axial T2 with fat

60:33

saturation, again using fast spin echo technique or a

60:36

turbo spin echo technique, depending on your vendor.

60:38

And, uh, and then we can go from there.

60:41

Uh, and so we do try and

60:43

tailor it and keep it limited.

60:45

Uh, what we normally do.

60:46

When you say routine MRI sequence, we review

60:49

our protocols every year and we have discussions

60:52

about the ones that seem to take a little bit

60:53

longer time, especially the sedated patients.

60:57

And so we go back and look to see where

60:59

we can try and cut down on some of our

61:01

sequencing with some of the faster techniques.

61:04

It still makes for a relatively short exam.

61:07

I do like to follow, uh, with MRI for neuroblastoma.

61:10

Again, it's not typically to the lungs.

61:12

When I've seen neuroblastoma go to

61:14

the lungs, it's usually in recurrence.

61:17

Uh, poor, um, pathologic, uh, prognosis.

61:21

Um, you know, again, um, a patient who's

61:25

already been treated, who now has,

61:27

is having a relapse and a complication.

61:30

And so I'm not typically looking for

61:32

lung, uh, nodules and metastases with CT.

61:35

And so I like MRI and neuroblastoma together.

61:38

Again, the age of the patient, you have to take

61:40

into account the issue of sedation with Wilms tumor.

61:44

At our institution, we do a lot more CT imaging.

61:48

And so that's why we're very careful

61:50

about, uh, multiple, uh, phase, uh,

61:53

acquisitions, which we do not do.

61:55

And, uh, dose reduction technique, we're very,

61:58

very careful about that and, and very cognizant

62:01

of that in part because we know that we can

62:04

do all the imaging with Wilms with one exam.

62:07

And number two is, uh, for some of the renal

62:09

surgery, especially our, uh, pediatric surgeons,

62:13

like to look at CT, uh, they find that a lot easier

62:17

for them when they start to make their planning.

62:19

But if, if all things were created equal, I,

62:22

I like to do MRI for both if at all possible.

62:26

Um, when screening with ultrasound in Beckwith,

62:29

what do you look for with regards to Wilms tumor?

62:33

So we've seen, um, multiple variations on...

62:37

The appearance of the kidney with just

62:39

patients with Beckwith-Wiedemann syndrome.

62:40

I've seen ones where they have

62:42

multiple diffuse, uh, echogenic foci.

62:45

They have some loss of cortical

62:47

medullary differentiation.

62:48

Others that look more normal for age.

62:51

On ultrasound, I think what we're

62:53

really looking for is any focal masses.

62:55

And so I, I do recommend, especially in the

62:58

younger patients, uh, maximizing your technique,

63:01

using linear, uh, transducers, uh, trying to

63:05

maximize the, um, the frequency that you use, the

63:09

focal point, the focal zone, the, um, the field

63:14

of view, all of that, uh, to try and, uh, best

63:17

maximize your ability to pick up subtle masses.

63:19

But really we're looking just to see if

63:21

there's any mass effect or any new changes

63:24

to the kidney, if we have a previous one.

63:28

Um, I don't know.

63:29

Dr. Ahmad's, uh, question on

63:31

the XP10 gene translocation.

63:34

And how does it apply to, uh,

63:35

pediatric renal cell carcinoma?

63:37

Uh, that's a great question.

63:39

I'd have to look that one up.

63:41

I don't know the answer to that one.

63:43

Um, I, uh, have been at Michigan for the

63:46

past three plus years, um, after having

63:49

practiced pediatric radiology in other places.

63:52

Um, and I personally can't remember the last

63:54

time I've seen an RCC in a pediatric patient.

63:57

It does occur, but I don't

63:59

have enough experience with it.

64:00

I would have to defer to my adult

64:01

colleagues who see that tumor more often.

64:05

Alright, well, as we bring this to a close, I want

64:08

to thank Dr. Bloom for this lecture, and thanks to

64:10

all of you for participating in our noon conference.

64:13

A reminder that this conference is

64:14

available on demand on mmrionline.com.

64:18

In addition to all previous noon conferences,

64:21

be sure to join us on Friday for a

64:23

lecture from Dr. Shake on MSK PET CT.

64:28

You can register for that at MRI Online.

64:31

And follow us on social media at The MRI Online for

64:35

updates and reminders on upcoming noon conferences.

64:38

Thanks again and have a great day.

64:40

Thank you.