00:02
Welcome back, to the final chapter
in our discussion
of optimal logic pathology.
00:08
We're going to finish up here
with ocular melanomas.
00:12
And although we think of melanoma
as being primarily a tumor of skin,
they can also occur in the eye.
00:21
And with some
devastating consequences.
00:24
Just as a trigger warning,
some of the images are not
particularly attractive.
00:30
I will try to give you a warning.
00:32
But know, that this is just
the way that pathology looks.
00:38
Okay. With that warning,
let's get going.
00:41
The epidemiology
of ocular melanoma.
00:44
So, if you stopped and thought
about it for a minute, you'd say,
"Well, I would expect that
ocular melanoma would occur
in areas where there are
more pigmented cells.
00:54
So I would expect it to be
really, really common in the iris."
Not so much.
00:59
Actually, the choroid has the
greatest density of ocular melanoma.
01:04
So, about 80% of eye melanomas
will occur in the choroid.
01:09
And we don't really think about
the choroid is having, you know,
a lot of pigmented cells,
but yet, there are melanocytes
that are there.
01:16
The ciliary body is kind of next.
01:19
And although
it doesn't have particularly
a lot of pigmented cells,
there are melanocytes
that are present there.
01:27
So, about 10%.
01:28
And then iris and conjunctiva
come in
kind of a distant third,
overall.
01:33
So, most of these
are going to be choroidal.
01:35
And, so therefore, they won't be
necessarily directly visualizable.
01:40
If you get a melanoma
of the iris,
you're going to kind of know
about that.
01:44
If you get a melanoma of the choroid
you may not.
01:48
The peak incidence is 50 to 70.
01:50
So, it tends to be a disease
of older folks.
01:53
So, those medical students
on this session
shouldn't worry about it
too much yet.
01:57
But as you get older,
there's increasing incidence.
02:01
So, what are the
risk factors for this?
So, light skin color,
so melanomas in general,
will have certain risk factors.
02:08
And all those risk factors are also
going to be largely the same,
when we talk about
ocular melanomas.
02:14
What's shown in the green box
is actually an iris melanoma.
02:18
It's just because
it's a good image,
and melanomas are going to typically
be pigmented black lesions.
02:25
Light skin color
put you at increased risk,
probably because
you have a potential
for greater UV penetration,
and therefore,
a greater propensity
to cause mutations
in melanocytes.
02:38
If you have a number
of cutaneous nevi,
that is particularly those
that are atypical,
that will put you
at increased risk,
because you probably have
atypical ocular melanocytes.
02:50
Light eye color
allows more UV light through.
02:54
If you have existing nevi
in the eye,
that typically will put you
at a slightly increased risk.
03:01
And obviously,
if you have choroidal nevi,
and those men, most of us
who might have choroidal nevi
won't know about that
until you have your first
optimal logic exam,
because there's just absolutely
no manifestations.
03:17
So, one of those
not so pleasant pictures.
03:20
The mortality rate is dependent on
which part of the eye is involved.
03:27
So, the ciliary body has about
a 30-50%, 5 year survival rate.
03:34
Melanoma of the iris
much worse, actually.
03:38
So, it depends.
03:40
And remember
the vast majority
80% of melanomas
are going to be coronal.
03:45
So, that gives
the following statistics
than last two bullet points,
since most of the melanomas
are going to be choroidal.
03:54
It doesn't necessarily
follow those statistics
for the ciliary body
in the iris.
03:58
If you catch it
at an early stage
when it does not spread
to surrounding tissues or nodes,
overall, you have an 85%
5 year survival.
04:06
Now, it's very likely that it will
catch up with you at 10 years,
but at least at five years,
it's pretty good.
04:12
And then, if it's spread to
surrounding tissues, and or nodes,
then it's a 71% survival.
04:23
What are the signs and symptoms?
Again, we're showing you,
actually now, a nevus
that is on the eye itself,
kind of in the conjunctiva.
04:37
But this will hold true for
a whole variety of melanomas
including those that are
predominant within the choroid.
04:44
In the choroid in particular,
you will tend to get blurry vision
because you are distorting
how the retina sits relative
to where the focal point is
of what the lens
is bringing in terms of light.
04:56
So, you'll have blurry vision,
and depending on the size
of the tumor,
you may have distorted vision
just because of the tumor mass.
05:03
In the choroid, you may have
visual field defects.
05:06
So, a choroidal melanoma
is much more likely to do that.
05:09
The conjunctiva melanoma
that's been shown here
probably not so much.
05:14
You may have
abnormal inhomogeneities
within the vitreous fluid.
05:23
And so that may give rise
to floaters, in the field of vision.
05:28
And you may also have
flashes of light
so called photopsia.
05:33
And again, this is because of tumor
that sits mostly within the choroid.
05:38
Tumor of any form, in any place,
will likely distort the pupil shape,
and that can lead to
changes in vision.
05:49
Defined the coronal melanoma,
you'll see a
darkened subretinal mass.
05:53
So, this is something
that would show up
on our fundoscopic exam,
but might not otherwise
be visually apparent.
06:00
And with that, we kind have covered
melanomas of the eye
and we are at an end
of ophthalmologic pathology.
06:10
With this,
this gives you a good start
to think about ophthalmology,
think about diseases of the eye,
and hopefully,
you had a better understanding
of how the eye is assembled.
It's an incredible structure.
06:21
And without that,
you wouldn't even be able to watch
what we've just done.
06:26
And with that, we'll close.