00:01
Welcome.
00:02
In this talk,
we're going to cover MALT lymphomas.
00:06
This has nothing to do with
malted milk or malt in beer.
00:11
This has to do with mucosal
associated lymphoid tissue lymphomas.
00:17
So MALT, as I've already said,
that's the abbreviation lymphoma
are typically quite indolent non-Hodgkin's
lymphomas that arise in lymphoid tissue
associated with various mucosa.
00:28
And it's usually occurring in the
setting of chronic inflammatory states.
00:34
Let's look at some of
the epidemiology here.
00:36
So overall, if we look at all non-Hodgkin's
lymphomas anywhere in the body,
roughly 5%-10% of them are going to be
mucosal associated or malt lymphomas.
00:48
The highest incidence for a variety of
reasons, some of which I don't understand,
are in non-hispanic whites.
00:57
It's primarily seen
in older individuals,
the median age at diagnosis is
somewhere about 65 years of age
or the usual social
security retirement age.
01:08
It's associated as I've already said,
with chronic inflammatory states,
and typically chronic inflammatory
states associated with various mucosa.
01:18
What is happening is
with that inflammation,
we are driving in the draining lymph nodes
proliferation of the marginals zone B cells
that's the appropriate response in a lymph
node with a localized area of inflammation.
01:31
But if we drive that over
and over and over again,
we will eventually acquire
mutations that will lead
to the formation of a
non-Hodgkin's lymphoma.
01:42
So as you might expect,
in terms of pathophysiology,
autoimmune disease,
and chronic infections that never clear
are going to be major
drivers of these lesions.
01:54
Of the autoimmune conditions,
this is just a partial list
but Sjögren's syndrome
associated with sialadenitis.
02:01
And so you would have mucosa
associated with the oropharynx
that could develop
MALT lymphomas,
lupus, relapsing polychondritis,
Hashimoto's thyroiditis,
again, a partial list.
02:15
Chronic infections,
and there's a long list there.
02:17
This is only partial, but the one you
should remember is Helicobacter pylori,
and that's going to lead predominantly
to gastric mucosal MALT lymphomas.
02:30
How is this happening?
So we're showing a schematic more or
less of the epithelium lining the stomach
and kind of grazing
over the surface,
you see all the spirochetes
representing the Helicobacter pylori.
02:44
Deep to that within
the submucosa,
we are looking at nodal tissue.
02:50
So nascent lymph nodes
that are being driven
by things an antigen stimulation
draining off of the epithelium.
02:59
With prolonged bouts of
inflammation here represented
by all of the neutrophils and the
macrophages and the lymphocytes,
we're going to eventually,
with that ongoing inflammatory process,
have a number of antigens that are going to
drain appropriately into the nodal tissue
and we're going to get the
appropriate immune response.
03:23
And we will get an elaboration
within the marginal zones
of the B cells that would normally be
responsible for fighting off the infection.
03:32
So we get these rather large,
very prominent nodal proliferations.
03:38
You see above that we've
had some epithelial injury
and that may be part
and parcel of this,
but the epithelium doesn't even
need to be particularly damaged
just with chronic inflammation.
03:49
There are various markers of the
cells that are proliferating,
so c-myc and bcl10.
03:55
There may be over time
additional mutations
that are acquired
including translocations.
04:00
And in these
proliferating nodes,
we will get the development
of MALT lymphomas.
04:06
This is just showing you the
histology what that looks like.
04:09
It looks like a lymphoma anywhere else
except it happens to be in a mucosal bed.
04:14
So the clinical presentation will
depend on the underlying etiology
whether it's autoimmune
or infectious.
04:20
And then some of the other
secondary manifestations
depending on the
size of the tumor,
and depending on its location,
you may have reflux disease,
you may have epigastric
pain or discomfort.
04:33
If it get a large
enough tumor mass,
you may develop as a
result of the tumor itself.
04:38
Secondary anorexia,
with that may come weight loss,
you may have a occullt GI
bleeding due to mucosal erosion
overlying these rather
large nodal proliferations.
04:50
And the symptoms
wherever they occur
are going to be largely
reflective of the local anatomy.
04:57
Making the diagnosis.
04:59
You can do a peripheral blood
count and a differential.
05:03
Usually in lymphomas as
you're undoubtedly aware,
you will not see necessarily
in up regulation and the number
or even the abnormal behavior
of peripheral blood lymphocytes.
05:17
You may see as a result of
turnover of the MALT lymphoma
and elevated lactate dehydrogenase,
so LDH will be elevated.
05:25
You do want to rule out other potential
etiologies, such as multiple myeloma.
05:30
So you would do a serum
protein electrophoresis
to evaluate for
monoclonal gammopathy.
05:35
Thirdly,
you would want to do imaging.
05:37
CT and MRI to look for the extent
of disease and where disease is.
05:41
PET and CT can also be done.
05:44
And then you want to biopsy it.
05:45
Of course, because I'm a pathologist,
everything comes down to the biopsy.
05:49
This is no exception,
you need to know what you're dealing with.
05:52
Because the specific
therapy for MALT lymphomas
will be driven by their
underlying etiology
and the therapy is different let's say
for a carcinoma or for a GI stromal tumor.
06:05
The markers for these
tumors, the MALTomas
are going to be very similar to
what's in a marginal zone lymphoma,
elevated CD19,
and an elevated CD20.
06:16
Those are typical markers of
proliferating marginal B cells.
06:22
They're going to be
CD23, another marker
that's typically seen in
mantle zone lymphomas.
06:29
Probably not necessary
that you remember that,
it is necessary to remember
that there are specific markers
and that biopsy is how you're going
to be able to make the diagnosis.
06:38
How are we going to manage this?
Well, in fact,
because we know in many cases,
these are driven by
chronic infections,
let's treat the
chronic infection
and get rid of that
inflammatory stimulus
that's driving the
proliferation of these cells.
06:53
So if if we know or
suspect that it's,
for example,
secondary Helicobacter pylori,
we can do eradication therapy
with triple antibiotics.
07:03
We can do follow up serial endoscopies
to make sure that these tumors
can regress and they frequently do once
we take away the antigenic stimulation.
07:13
In the cases where
they don't regress,
then we can treat with radiation
or systemic chemotherapy.
07:19
And in instances where
we have perforation,
uncontrolled
bleeding, obstruction,
we may actually have to
progress to gastric resection.
07:29
The prognostic factor is things
that have a worse prognosis.
07:31
So the older you get,
the worse prognosis.
07:34
Stage lll and lV disease where
you have much more systemic spread
rather than just locally within a
particular spot in the GI tract.
07:45
Serum LDH levels
that are very high,
indicating that we have a lot of
cellular turnover within the tumor.
07:53
And depending on the
various prognostic factors,
depending on response to
therapy, all of those things,
5-year survival is not terrible.
08:01
And in fact, in some cases where it's
more indolent and more localized,
it's almost 100% survival.
08:09
So, you've now learned about
MALT, lymphomas or MALtomas.