MRI Solid Pancreatic Tumors

Introduction: Case Example of Pancreatic Adenocarcinoma

I'm gonna start with a known case,
and this illustrates very nicely the utility of MR in the evaluation of a lot of these solid pancreatic lesions.
I'm gonna start with a CT examination,
and you can see here nicely,
you can see duct dilatation, right?
Sort of abrupt onset of duct dilatation.
Kind of hard to tell why.
In this specific patient, we proceeded with an MR,
and I'll start with the T two weighted images.
And again, these confirm the presence
of distal duct dilatation.
Again, this is a very concerning finding to begin with,
but as you can see here, the contrast enhanced
and dynamic MR examination nicely showed us the reason
for the duct dilatation.
And this is a case of pancreatic adenocarcinoma.
Just a synopsize, we had a lesion that was not seen on CT only.
We saw the pancreatic duct dilatation.
However, the MR better depicted the mass, which was hyper enhancing early
and demonstrated gradual increased enhancement.
And this is classic for pancreatic adenocarcinoma.

Pancreatic Adenocarcinoma: Statistics and Treatment Goals

These are the fourth most common cause
of cancer related death in the United States.
And unfortunately, the five year survival is quite dismal,
only 5% at diagnosis.
As you can see here, 45% of patients metastatic,
40% locally advanced and only 15% are surgical candidates.
The recent goal since surgery is the only hope has been
to increase the number of patients who can undergo surgery.
And there's been an increased trend in the use of venous
and hepatic arterial interposition grafts
and also the use of pre-op chemotherapy and or XRT.

MDCT Protocol for the Pancreas

I'll start very briefly talking about the MDCT protocol done for the pancreas, which consists of a pre contrast,
a pancreatic parenchymal phase of 35 to 45 seconds.
And this best depicts the primary tumor
and the mass will appear ill-defined
and hypodense followed
by portal venous phase at approximately 60 to 70 seconds.
And this best demonstrates involvement
of the venous structures and liver metastases,
and the primary tumor actually may be less apparent
or even isodense.
The overall sensitivity of MDCT
for pancreatic cancer is anywhere between 86 and 97%.
However, the sensitivity
for smaller lesions under two centimeters is probably closer
to 77%.
Dual energy CT has shown promise,
but this has not yet been validated in the literature.

Classic Imaging Findings on CT

A couple of cases, very classic imaging findings.
In this specific case, we have a hypo enhancing mass
and we have an abrupt cutoff of the pancreatic duct,
which is dilated distally.
Very classic imaging findings for pancreatic cancer.
Here you can see the corresponding coronal reformatted
images showing the hypodense mass
and also the distal pancreatic duct dilatation.
No significant atrophy yet of the distal pancreas,
as you can see in this case here, which is a more advanced cancer, again, a hyper enhancing mass.
And you can see that you have near obliteration
of the distal pancreatic parenchyma
and massive dilatation of the pancreatic duct distally.
CT also nicely, as we know,
depicts the vascular involvement.
We can see very good detail when we look at the different vessels that we have to look
for when we report these patients.
Here's another case, again, similar findings.
Here you can see distal atrophy,
distal duct dilatation, a mass
that actually invades the duodenum.
Very classic for pancreatic adenocarcinoma.

Limitations of CT: Iso-attenuating Tumors

One of the problems with CT is
that there are iso attenuating tumors on CT, meaning
that 5.4%
of pancreatic cancers are truly iso attenuating on both
phases of a pancreatic protocol CT.
And a study that was done published in radiology in 2010
of these iso attenuating tumors on CT
and MR showed a sensitivity
of almost 80% in picking these up
and even better than the PET CT sensitivity
of just under 74%.
MR obviously would be very useful
for follow up of these tumors.

MR Protocol for Pancreatic Imaging

Very briefly, this is our protocol that we use.
We do in phase out of phase gradient and ECHO T one.
We use axial and coronal T two HASTE
or single shot fast spin echo.
Then we do a turbo spin echo axial fat suppressed T two.
We do diffusion sequences.
Then we also do, this is part of our MRCP axial
and coronal thin section HASTE
or single shot fast spin ECHO T two weighted images.
We use a 3D turbo spin ECHO navigator triggered MRCP,
and we also obtain axial and coronal RARE T two sequences.
And of course, axial and coronal pre
and dynamic post gadolinium T one weighted images.

MR Appearance of Pancreatic Adenocarcinoma

How about the MR appearance of pancreatic adenocarcinoma?
For one, there's superior tumor conspicuity
and non-contrast MR.
Much better than we can see in a non-contrast CT.
The tumors are hypointense
and fat saturated non-contrast T one.
And that's because this is in contrast
to the high signal intensity,
normal pancreas, as I showed you earlier.
And the tumors have abundant desmoplastic stroma,
and that causes this appearance.
The tumors are hypo enhancing early,
and the masses may typically show some gradual
enhancement over time.
The T2 signal appearance is somewhat variable
and we'll talk about some of this in a second.

Case Examples of MR in Pancreatic Adenocarcinoma

Here is a distal tail pancreatic adenocarcinoma.
I'll show you some images. Non-contrast study
hypointense mass.
Here you can see in the T two weighted in this specific
case, it's a relatively isointense mass,
although the variable,
in some cases they are hyperintense,
restricted diffusion was seen.
And we'll talk a little bit about restricted
diffusion in these cancers.
And as you can see on the arterial phase imaging,
quite hyper enhancing.
And then there's some sort of gradual increased low level
enhancement of the mass over time.
Here's another case
and you can see a CT showing a hypodense mass in the distal aspect of the pancreas.
And you can see in the T two fat sat, in this specific case,
it's hyperintense. On the pre, again, you can see
how nicely it contrasts with a normal adjacent pancreatic parenchyma.
It's hyperintense arterial phase imaging, hyper enhancing,
and then eventually, especially in the delayed images.
So some enhancement.
Here's yet another case.
And here just to illustrate the so known double duct sign,
which is very classic for pancreatic cancer in the pancreatic head near the ampullary region.
Here's yet another case.
In this specific case, you can see again,
same imaging features
and also nicely you can see the cutoff, abrupt cutoff
and distal duct dilatation associated
with this malignancy.
Not to tire you, I'll show you just another case or two.
Again, same imaging features.
Here's the CT
and I'll follow this with this corresponding MR.
Hyper enhancing mass seen pretty well on the CT.
Also seen very well in the MR.
You can see it slightly hyperintensity in the T two fat sat.
You can see very non enhancing essentially
or very hyper enhancing on the arterial post.
And then subsequently
or in the delayed images, you can see there's
increased enhancement of the mass.

Comparison of MR and CT for Pancreatic Cancer

How about comparing MR to CT contrast?
Resolution of MR is no question superior.
And also there's no question that spatial resolution
of MR is inferior.
So CT could be preferred over MR
for initial staging of these cancers.
As a matter of fact, the National Comprehensive Cancer
Network guidelines recommend CT for staging.
There have been many studies in literature, however, that state,
including this study here from JMRI from 2009, that
MR has similar performance even in the early
phase when we're doing staging.

Vascular Involvement Assessment

How about vascular enhancement?
Here are a couple of cases where you can very nicely see,
there's no question about it.
Arterial encasement,
and venous encasement as you can see here.
Here's another case.
You can very nicely see the soft tissue with arterial
encasement of the mass.
So in certain cases we can see it pretty well.
There are other cases, however,
where it's a little bit more problematic
and in this case, I don't think there's a question
that there is encasement of the hepatic artery.
See how much better detail you see on
the CT in some cases.
And again, that's due to the spatial resolution.
Here is an endoscopic ultrasound
that was subsequently performed confirming
what we already knew, that the mass was causing encasement of the hepatic artery.

Indications for Preferring MR in Pancreatic Adenocarcinoma

There's several other instances when MR could be
preferred in the setting of pancreatic adenocarcinoma.
And that includes smaller lesions evaluating the enlarged
pancreatic head or tail peripancreatic
and unprocessed lesions,
detecting the isoattenuating tumor in CT,
distinguishing from benign fatty infiltration,
and also evaluating for the presence of small liver mets
or for evaluating for other liver lesions
that may be coexistent.

Reporting Requirements for Pancreatic Adenocarcinoma

Our task in pancreatic adenocarcinoma, obviously,
no matter whether we're reading a CT
or an MR, is to identify the tumor
to evaluate the peripancreatic fat,
the lymph nodes, the surrounding structures.
We have to evaluate the vessels in detail
and report them in detail.
We have to describe the length
and circumference, whether it's under 180
or over 180 degrees,
and the location of contact that we have
to look at all the pertinent arteries.
And we also have to include variant arterial anatomy
and also all the pertinent veins.
And we're all very familiar with all these
structures that we have to report.
And if it's a venous structure, we have
to include information regarding whether there is occlusion
and if so, the length of the occluded segment.
Of course, we also have to evaluate for metastases
and the typical areas, liver, nodes, lungs.
And one thing we must not forget is the peritoneum
'cause I've seen a couple of cases over time in our QA conferences where actually there was peritoneal metastasis.
They had talked about everything,
but they had missed the peritoneal metastasis.

Diffusion-Weighted Imaging in Pancreatic Adenocarcinoma

Regarding diffusion weighted imaging
and pancreatic adenocarcinoma.
There have been numerous studies showing significantly lower
ADC values in pancreatic adenocarcinoma.
There was a study in 2012 in radiology from Japan showing
that DWI was not useful for delineating adenocarcinomas due
to the hyperintensity of the pancreatic
parenchyma distal to the tumor.
A more recent study out of NYU showed
that there's no association between ADC values
and anything such as tumor grade
or other pathologic features including grade, stage.
Notice that status or location.
Here's a very obvious case of a pancreatic adenocarcinoma,
and as you can see here, restricted diffusion
with a lower signal in the ADC map.
And in most cases, actually,
diffusion weighted imaging is sort of an adjunct
that just basically helps us
and helps us look for sites of distal disease
or sites that we're not expecting disease to be present.
Here's an interesting case.
This is sort of a diffusely infiltrative mass,
no pancreatic duct dilatation on the CT.
You can see just a large mass.
You can see it's very hyper enhancing on the arterial
phase MR
and subsequently it had a little bit
of increased enhancement.
And you can see the whole mass had restricted diffusion
on ADC.

Mimics of Pancreatic Adenocarcinoma

Focal Fat Infiltration

There are some mimics of pancreatic adenocarcinoma.
I'll mention just a few, one of them being focal fat
or fat infiltration, focal pancreatitis, lymph nodes,
and other pseudomasses.
And here's a couple cases of focal fat infiltration.
You can see in this specific case, you can see an area
of relative hypo enhancement
and the unprocessed T two signal was a little bit slightly heterogeneous,
and the in and out of phase images are
what basically made the diagnosis.
And I know this slide is showing a little bit dark,
but there's definite drop of signal in the out phase images.
I'll show you a couple more such cases.
Again, here you have a potentially suspicious area
of hyper enhancement on the arterial phase imaging.
And you can see very nicely the out phase image shows a drop of signal and yet another case.
And just to show you that these can occur in more atypical
locations, this is an area in the
tail actually of the pancreas.
And you can see same features signal drop
out in out of phase images.
And this is an atypical area of focal fat infiltration.
Just as an aside, this is a case to show you where we have actually macroscopic fat within
the pancreatic lesion.
And given that it's macroscopic fat
and it's behaving like microscopic fat,
this actually ended up being a case of a pancreatic lipoma.

Focal Pancreatitis

A couple of issues that may occur.
Sometimes this is a case of focal pancreatitis
mimicking pancreatic cancer.
You can see a hypodense mass distally.
You can see maybe some duct dilatation.
Definitely a lot of stranding.
We weren't sure actually if the stranding was tumor
invasion or if it was just like this distal pancreatitis.
We performed an MR subsequently,
and you can see again the same features.
It was a little bit later, so maybe we lost a little bit
of those sort of inflammatory changes in distal aspect
of the tail of the pancreas distal to the mass.
This was by biopsy proven to be pancreatitis, focal pancreatitis.
And there've been many papers discussing
how do we really tell apart cancer from
mass forming pancreatitis.
I'll just very briefly mention a very recent article from Indiana in AJR
and they said it's very difficult
to differentiate mass forming chronic pancreatitis from
pancreatic cancer in MR.
And the presence of a well-defined mass was
the only helpful sign.
Diffusion was not helpful,
and even they found interesting that double duct sign,
pancreatic duct cutoff perivascular soft tissue cuffing were
not useful in differentiating between these two groups.

Autoimmune Pancreatitis

Very briefly, this is another case, kind
of similar to what we saw before.
Here's so-called focal enlargement
of a portion of the pancreas.
You can see sort of non visualization
of the pancreatic duct in that area.
You can see further approximately the pancreas is normal in
caliber,
and these are just very classic imaging features of autoimmune pancreatitis.
So this is another potential mimic,
but there's no way we should not make this diagnosis.

Intrapancreatic Spleen

Here's another sort of case.
Look at it for just a couple of seconds as an unknown.
So what we're looking at, we're looking at the mass here in the very distal tail aspect of the pancreas.
So that's the area that we're looking at.
So this is a case of an intrapancreatic spleen.
So these are quite common as we've seen them very frequently in other locations in the left upper
quadrant, they're congenital in origin,
most commonly near the splenic hilum,
but about 20% are either in or near the pancreatic tail.
What's key is that we see similar imaging characteristics
to the spleen on all the sequences.
And in some cases we could get confirmation
with nuclear medicine studies, but usually MR will suffice.
And in some cases we may even do a follow up here.
Again, I'll show you just these images once more.
You can see identical signal intensity to the pancreas,
I'm sorry, between the mass and the pancreas and the spleen.
Here you can see the same in the pre gad, the same,
you can see almost a speckle appearance, same
as we see in the spleen.
And more delayed.
You can see the same pattern of enhancement.
Here's another case. Same diagnosis.
This is a little bit harder actually to for sure make the diagnosis.
This actually was followed in a short term interval, and this was another case
of an intrapancreatic spleen.

Pancreatic Neuroendocrine Tumors

Here's the next case. I'll just give you a couple
of seconds to look and see
and make your opinion as to what you think is going on.
We have this little mass, same thing over here.
And over here in a more delayed post gadolinium image.
So the main findings, a small lesion, which is T one hyperintense and arterial enhancing.
So the main differential consideration
for this would be a neuroendocrine tumor of the pancreas.
These typically occur in young
to middle aged patients.
About 70 to 75% are sporadic,
approximately a quarter occur with MEN 1.
And they can also occur in these other syndromes.
Von Hippel Lindau and NF1 and TS.
Most are functioning.
And these will typically present earlier when they're
smaller, but there are non-functioning tumors as well,
that sometimes can be quite large at presentation
with more advanced disease.
So based on the World Health Organization categorization,
they're either neuroendocrine tumors, grades one and two
or neuroendocrine carcinomas, which is grade three.
And these grades are based on a mitotic
count, as you can see here.
So depending on how many mitoses per 10 high power fields
they see there, it's assigned a grade
and also what's called the Ki 67 index.
And again, you can see depending on this index,
the Ki 67 index, the grade of the tumor is assigned.

Staging of Neuroendocrine Tumors

Regarding staging very quickly.
T one tumors are those that are confined to the pancreas
and under two centimeters, if they're confined,
but over two centimeters, they're T two lesions.
T three is when we have peripancreatic spread,
but no major vascular invasion.
And when we have major vascular invasion,
these are T four lesions.
Here's actually a large such tumor.
Very classic appearance on CT.
You can see very avidly enhancing arterial mass
on the arterial phase imaging.
And this was a pancreatic neuroendocrine tumor.

MR vs. CT for Neuroendocrine Tumors

Now, how about MR versus CT for neuroendocrine tumors?
There are some studies that have shown relatively similar
performance of the two.
However, there are several other studies
that have reported superior sensitivity and specificity.
And these are the numbers with MRI.
Furthermore, MR has been shown
to be more sensitive than CT in detecting liver metastases.

MR Appearance of Neuroendocrine Tumors

So regarding the MR appearance,
typically they're low signal intensity in T one weighted
images, intermediate to high signal in T two.
And typically more uniform enhancement will be seen in
smaller tumors where larger tumors may be larger
and much more heterogeneous.
Now, pancreatic duct
or CBD obstruction may occur, but it's very infrequent.
And there have been a few papers recently
stating that if you see that you have
to consider somatostatin secreting neuroendocrine tumors.
And that's because they elicit a local fibrotic response.

Case Examples of Neuroendocrine Tumors

So here are some images. Again, this is the lesion
that I showed you earlier, hyperintense on the T one
weighted images, typically either isointense
or hyperintense on the T two weighted images.
And these are hyper enhancing masses.
And in fact, in this specific case,
there are two different lesions,
particularly in the arterial phase.
These are hyper enhancing masses.
This is very rough sort of way
of distinguishing adenocarcinoma from neuroendocrine tumors.
Adenocarcinomas are typically under four centimeters,
where neuroendocrine can be anywhere from like under one
centimeter to over 10.
Classically hypovascular early hypervascular, early
for neuroendocrine tumors.
Vascular encasement would be of course common
with adenocarcinoma and rare with neuroendocrine tumors.
Calcifications will be common with neuroendocrine tumors
and duct dilatation is just possible,
but not as common in neuroendocrine tumors.

Subtypes of Functional Neuroendocrine Tumors

I'll talk very briefly about some subsets,
some subtypes, and there's insulinoma is one of them.
It's the most common functional neuroendocrine tumor.
And usually these are quite small.
As you can see, 90% are under two centimeters
and 40% are under one centimeter.
These are more typically uniformly hypervascular,
quite homogeneous in their appearance.
Patients typically present with symptoms of hypoglycemia.
They tend to be benign.
They're malignant in about 10% of cases.
And if they're associated with the MEN syndrome,
then they can be multiple.
And then enucleation is a treatment of choice,
and we have to be very careful to evaluate the relationship of the tumors
with the pancreatic duct since they'll be
doing focal surgery.
Overall goal is to resect all sites of disease.
Gastrinomas are the second most common
functional neuroendocrine tumor.
And as we remember, these are associated
with the Zollinger Ellison syndrome,
where there is gastric acid hypersecretion,
and severe peptic ulcer disease.
Now, these can be larger, more heterogeneous,
75% occur in the so-called gastrinoma triangle.
And the borders of this are the cystic duct
and CBD, the neck
and body of pancreas, and the second and third portion.
So the duodenum.
Now the duodenum is quite frequently
involved in this patients.
So when there's surgical treatment,
actually it's very important that they do a duodenotomy
searching for additional tumors.
These are most of these are malignant
and they can metastasize to the liver and bones.
Very briefly, I just added a little bit about
these other tumors.
Glucagonomas are the ones
that secrete glucagon patients will present
with glucose intolerance, weight loss, diarrhea, migratory,
necrolytic erythema, and glossitis.
Typically, again, large heterogeneously enhancing
with liver metastasis when discovered.
And they're always located in the pancreas,
almost always in the body and tail.
And finally, VIPomas.
These are the vasoactive intestinal
polypeptide tumors.
The Verner Morrison syndrome is very classic, a triad
of watery diarrhea, hypokalemia and achlorhydria in adults.
Most of the VIPomas will arise from the pancreas.
And again, these are typically large
heterogeneous and metastatic.

Non-Functioning Neuroendocrine Tumors

I need to talk a little bit about
non-functioning neuroendocrine tumors.
And up to 50% of these are non-functioning,
and what they do is they actually may produce a hormone,
which is a polypeptide,
but this will not cause any effect
and it will cause no symptoms,
or they may not produce anything at all.
Typically, they're found incidentally or due to mass effect.
And often again, since they don't produce anything
and they're clinically silent,
they can present with advanced disease with liver metastases
and nodal metastases.
Cystic necrotic areas are frequent,
and calcifications can be present in a lot of these cases.

Case Examples of Non-Functioning Neuroendocrine Tumors

So let me show you some cases.
Here is another case classic imaging features.
You can see the mass,
and also in this case you can see a ring enhancing hepatic metastasis.
Here's a case,
and actually not all of them are seen
on the arterial phase imaging.
That's why I throw this specific case here.
In this specific case,
we saw it better on the pre contrast, as you can see here,
image, because again, it contrasts nicely with a normal
adjacent pancreas.
And we also saw it well in the diffusion weighted imaging.
As you can see here.
Here's another case
of recurrence after surgery.
And the diffusion actually helped us kind of identify
or be concerned about the different sites of disease.
It was much more clear actually,
how extensive the recurrence was on the diffusion weighted
imaging than on the regular conventional sequences.
Here's a larger neuroendocrine tumor,
and you can see on the top we have the CT
and the bottom, we have the MR.
You can see a large mass that is arterially
relatively hyper enhancing.
You can also see significant metastatic
disease in the liver.
Here's another large neuroendocrine tumor.
Again, we can see calcification of these.
This is the corresponding CT scan on the same patient.
Here's another patient
with a tail neuroendocrine tumor seen on MR.
Again, large sort of hypervascular,
a little bit heterogeneous mass seen on the MR.
The larger these tumors get.
Actually, they can get quite heterogeneous.
They can have large internal areas of necrosis,
as you can see on this other CT on this patient
with a metastatic large non-functioning neuroendocrine tumor.

Liver Metastases from Neuroendocrine Tumors

So regarding liver metastases, MR has been shown
to be more sensitive than CT.
Usually they're T two hyperintense.
Often they're well seen in the fat sat T two sequences
and enhancement early is either moderate or intense.
And in some cases we can see ring enhancement
and typically we'll see them pretty well in
diffusion weighted imaging.
And here is a patient, again,
you can see part of the tumor over here.
You can see how clearly you can see these arterial
hyper enhancing lesions.
Again, sometimes centrally, they're not
as enhancing the metastases.
And you can see them very clearly on
your T two weighted images.
And also you can see 'em very nicely on
the diffusion sequences.

Cystic Pancreatic Neuroendocrine Tumors

Very briefly, I wanted to talk
to you about cystic pancreatic neuroendocrine tumors.
And up to 13 to 17% have been described in the literature to be cystic.
And it's presumed that these are secondarily cystic.
But there has been a question whether these
are actually a distinct variant.
There is a recent study actually
that was published in AJR from Japan,
and they showed the incidence of small
and larger cystic neuroendocrine tumors were similar
and more typically these will demonstrate peripheral
enhancement, but a few may actually appear entirely cystic.
And here's a nice case.
I'll show you the CT and the MR starting with the CT.
You can see it's got a little very mildly thickened circumferential wall of the cystic lesion.
And you can see it very nicely on the MR the corresponding
lesion in the pancreatic tail.
This is a cystic neuroendocrine tumor.
Here's another case, larger lesion, less
of a perceptible wall,
but still a little bit of a thin wall seen
around here in this proximal pancreatic lesion.
Here's another cystic lesion.
There's some sort of internal debris here.
You can see nicely correlation
with the endoscopic ultrasound that was performed in this patient.
Here's such a patient.
Here's another patient with a partially,
at least partially cystic neuroendocrine tumor.
You can see the T two weighted images, a significant T two hyperintense component in this lesion.

Metastases to the Pancreas

I'm gonna move to another couple of other types
of solid lesions.
This is sort of the next unknown case.
Take a couple seconds to look at it.
So we have this sort of ill-defined mass.
We don't have pancreatic duct dilatation.
This image here is actually from a different cut.
It shows you part of this mass.
And actually the key to the diagnosis is here.
So actually this is a case of a metastasis from a renal cell carcinoma.
So metastases to the pancreas are uncommon
and they're usually seen in advanced disease, about two
to 5% is the incidence in the clinical setting.
And of course, higher numbers have been reported in autopsy
series, most commonly renal cell carcinoma,
but also can occur from lung cancer, melanoma,
and a variety of other primary malignancies.
One thing to note is the imaging characteristics
of the pancreatic metastases usually mimic
that of the primary tumor.
And they can be solitary, they can be multiple,
or they can have more of a diffusely infiltrative pattern.
So here's an MR with a patient with renal cell carcinoma.
You can see two quite subtle small lesions.
You can see them even on the T two fat sat images here.
And you can see them again,
these subtle small hyper enhancing foci
on the arterial phase MR.
Here's another patient here with a, actually a small renal cell carcinoma
and a large pancreatic lesion.
Actually, initially it was considered that probably this was
the primary and that might could have been a met,
but this was actually proven
to be a metastasis from a renal cell carcinoma.
Here's a CT again, you can see
how they mimic in enhancement pattern.
The primary tumors, they're usually very hypervascular,
at least the renal cell carcinoma mets yet another case illustrating the same point, very hypervascular mass
and arterial phase imaging.
Not quite as apparent on more delayed imaging.
This is another pancreatic met from RCC
and here two other patients.
And here you can see sort of more diffuse involvement of almost the entire gland.
In this specific case, you can see sort
of multifocal involvement of the pancreas.
And again, notice how avidly hyper enhancing these renal
cell carcinoma mets are.

Pancreatic Lymphoma

And finally, I'll talk very briefly
about pancreatic lymphoma.
Usually it's the non-Hodgkin's type.
Now primary pancreatic lymphoma is very rare.
It's only about half percent of pancreatic masses.
And most commonly, the pancreas, as you would expect,
is involved by direct extension from peripancreatic
lymphadenopathy.
There are two morphological types.
The localized, well-defined tumoral type
and also the infiltrative type
that replaces the whole pancreas.
Imaging features this as lymphoma elsewhere,
relatively hypodense
and non-contrast imaging on either CT or MR.
There's typically a mild low level homogeneous enhancement
that is seen vascular encasement that may be present.
Pancreatic duct dilatation is unusual
and typically we will see peripancreatic adenopathy,
and in many cases we may see disseminated
lymphadenopathy related to the patient's disease.
And I'll show you a patient here.
And this is really not
of any significant clinical consequence.
There's an unprocessed mass in this patient.
You can see the corresponding PET scan
and you can also see there's multiple masses in the kidney.
So this is just something to note and report.
And when we do our reports, here's another patient.
Here you can see another mass focal involvement with lymphoma.
A relatively hyper enhancing mass in the pancreatic head.
And again, you can see how avidly hypermetabolic it is on the PET scan.
And here you can see additional sites
of disease in the mediastinum in this patient with lymphoma.
Here's another patient where we have CT
and MR correlation.
The CT is here and here's the MR.
You can see like a mass, no distal duct dilatation.
This is a coronal image showing the same mass.
This was a case of pancreatic lymphoma.
This case here. We also have a couple of lesions.
This is another CT actually,
but we can see a couple of lesions in the pancreas.
Hypodense not causing pancreatic duct dilatation,
but in this case there are also areas,
and they're not very well depicted on this single axial
image here, but there are multiple areas that pan out
in the small bowel
of small bowel wall thickening in a patient with lymphoma.
Finally, here's a case of more diffuse involvement.
You can see this very large mass.
And here is sort of an older PET scan on an axial image
and a coronal image showing the extent of this mass
that is basically engulfing
and markedly expanding the pancreas.

Conclusion

So at this point, I want to end here we have just under a minute left.
This is my last lecture of the day.
I want to thank you very much for your attention.