Melanoma: Clinical Manifestation

00:00 The clinical presentation.

00:02 Let's go back and just briefly review the normal life of a mole.

00:07 A normal normal. A nevus.

00:10 A melanocytic proliferation that's not malignant.

00:13 So in normal skin you have scattered melanocytes that live at the dermoepidermal junction. Cool. They can proliferate.

00:20 You can get little nodules of those, and those are totally benign. That's kind of the junctional nevus that you see there with benign proliferations. Those cells, yeah they're proliferating not not hugely but they are. But they don't have the additional mutations that are going to drive metastasis or drive invasion.

00:44 Then in your normal moles, the normal lifespan of a normal mole is that you, with time may actually get cells that leave that dermoepidermal junction and dive deeper into the dermis. That will give you a compound nevus where you have cells in both places and they typically are more raised.

01:06 Okay. That's normal. And it's kind of the normal evolution.

01:10 And that's fine. And then you will get into dermal nevi.

01:14 So with time the cells may may no longer be at the dermoepidermal junction and their all dermal.

01:21 That's a dermal nevus.

01:23 And with time again, more and more years down the road, the normal behavior of the melanocytes that have done this have have started as a mole turn into neural like tissue neurodegeneration, and then they may not even be that pigmented.

01:41 So when we talk about regression of moles, that's kind of the process by which that happens okay. That's the normal kind of life of a mole okay. What happens with melanoma.

01:53 So you have an initial proliferation.

01:58 Um, but then it's not just proliferation, which is what happened with that normal mole. You acquire additional mutations that change the ability of the cells to differentiate, but also their behavior in terms of migration, invasion and other things that they're doing.

02:17 Tumors. So initially you may get a dysplastic nevus.

02:23 The cells look a little bit weird. They've acquired some additional mutations. They are not invasive. They are sitting there excision at that point completely curative. Typical typical melanomas.

02:36 If they're going to progress now we'll go through a radial growth phase where they tend to move radially. They are moving side to side.

02:44 And a few may go down into the dermis.

02:47 That can be a fairly long period of time.

02:51 And if we catch melanomas at that stage they're usually curable by a resection.

02:56 However, they then evolve to the next stage.

02:58 They will have a vertical growth phase.

03:01 They will now form large clusters that dive deep into the dermis, looking for lymphatics, looking for blood vessels, looking for other things.

03:12 And that's when you get metastatic melanoma.

03:15 So it's acquiring additional mutations beyond just the ability to proliferate.

03:23 How do we recognize moles.

03:24 Okay. So this is something you should kind of put in the back of your mind and for yourself for your patients, for your family, because everyone will come up to you at a cocktail party and say, do you think that's cancer? Now you can kind of give them a yes or no.

03:38 So there are the ABCDEs of melanoma diagnosis, grossly so with your naked eye.

03:44 So there's asymmetry. Benign lesions tend to be relatively symmetric oval or round. And if there's asymmetry there are little things sticking off on one side that aren't on the other.

03:55 That's a sign that makes you more worried about malignancy.

03:58 B is the border. Is it a smooth well-demarcated border, or is it kind of irregular and jagged and indented? C is color. So is the lesion one uniform color or is it got multiple colors? And if there's multiple colors, that's an indication that the melanocytes in there are beginning to diverge from making the same amount of melanin.

04:23 So there are going to be that's an indication that there are mutations.

04:26 D is the diameter. Is it less than six millimeters? Is it greater than six millimeters? Six millimeters is kind of the sweet spot.

04:34 If it's less than that much more likely it's benign.

04:37 If it's greater than that, significantly greater actually then it's more likely to be malignant.

04:43 And E is it changing. Is it evolving? And if you have seen growth, if it's now getting bigger, if it is growing up, if it is bleeding, if it is changing its colors.

04:58 All that evolution also speaks to new mutations that are being acquired.

05:03 So the A, B, C, D, E, s of gross melanoma diagnosis.

05:07 The types of melanoma.

05:09 So the most common is going to be the superficial spreading.

05:13 This is in the radial growth phase.

05:15 And we'll catch it at that point and resect it.

05:17 That's kind of why it's more common than in the nodular melanomas, which are going to be more of the vertical growth phase and tend to indicate more rapid growth. And those tend to be bad or worse actors overall. There's the lentigo maligna, uh, form of melanoma, which is also going to be mostly kind of a, a lateral growth, uh, and it can transition to a vertical growth phase at a future time.

05:51 And then there is the acral lentiginous melanoma.

05:55 These are ones that are associated with the palms the soles or the nail beds.

06:00 These are also going to be the more common variant seen in people of color. And for historical reference, Bob Marley of The Wailers, who was a famous musician in Jamaica, died of acral lentiginous melanoma that metastasized amelanotic melanoma. This seems like an oxymoron.

06:25 Melanoma cells don't need to make melanin to be a melanoma. In fact, in many cases they will quit making melanin because it's not a necessary component of their identity.

06:36 So amelanotic melanomas are white or tan, and they consist of very poorly differentiated and differentiated melanocytes, no longer making melanin.

06:45 So the present is lightly colored, flat or raised lesions.

06:49 And you go, oh, that's not a melanoma, that's something else. And we may delay the diagnosis. So they can be confused with benign lesions.

06:56 So you have to have a little bit of an index of suspicion.

06:59 Melanomas that also start off as pigmented may lose pigmentation.

07:03 Remember that changes in color that I talked about previously.

07:07 Spitz nevus is an interesting character.

07:09 So these were thought to represent malignant melanomas.

07:15 They in fact, if you look at them under the microscope, you would go, ooh I think that that's cancer.

07:21 They look very bizarre.

07:22 But they are not melanomas.

07:24 They are benign nevi. They are acquired melanocytic nevi.

07:29 They typically occur in kids.

07:32 They do not have any malignant behavior.

07:36 And they are characterized by very, very rapid growth.

07:39 So you would think, oh my God, this is the worst thing in the world. Now if you have one, you have a lesion in someone who's relatively young, more likely to be Spitz than it is to be a melanoma.

07:50 So interesting.