Bolognia Clarification Re: melanoma and dermoscopy

[DermDudeMD]

"For a lesion to be considered melanocytic, needs to have at least one of the following dermoscopic structures/features: pigment network, streaks, etc.."

If it does not, then evaluate for dermoscopic features of other entities (SK, dermatofibroma, etc)

HOWEVER, if the lesion DOES NOT have any features of a melanocytic lesion AND does NOT have any features of a non-melanocytic tumor, then by default the lesion is considered to be of melanocytic origin.

Can someone clarify this for me? So basically if the lesion does not have features of melanocytic or anything else, it is melanocytic by default? Maybe expand on why it defaults to melanocytic and not anything else. Thanks

edit: it's paraphrased

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[asmallchild]

"For a lesion to be considered melanocytic, needs to have at least one of the following dermoscopic structures/features: pigment network, streaks, etc.."

If it does not, then evaluate for dermoscopic features of other entities (SK, dermatofibroma, etc)

HOWEVER, if the lesion DOES NOT have any features of a melanocytic lesion AND does NOT have any features of a non-melanocytic tumor, then by default the lesion is considered to be of melanocytic origin.

Can someone clarify this for me? So basically if the lesion does not have features of melanocytic or anything else, it is melanocytic by default? Maybe expand on why it defaults to melanocytic and not anything else. Thanks

edit: it's paraphrased

I'm not sure that's a hard and fast rule. Essentially, I'd read it as: if I can't tell whether the lesion is melanocytic or non-melanocytic on clinical and dermoscopic exam, it's coming off via biopsy.

 

[DermDudeMD]

I'm not sure that's a hard and fast rule. Essentially, I'd read it as: if I can't tell whether the lesion is melanocytic or non-melanocytic on clinical and dermoscopic exam, it's coming off via biopsy.

Thank you! And I would assume you would proceed with an excisional biopsy with 2mm margins?

 

[asmallchild]

Thank you! And I would assume you would proceed with an excisional biopsy with 2mm margins?

It depends on the site but yes, in general, I prefer to avoid shaving melanocytic lesions.

 

[Dral]

That part of the algorithm takes you back to melanocytic so you hopefully don't miss an amelanotic melanoma.

 

[Decicco]

This is just one of several algorithms. The idea is to assume something is melanocytic (ig, a possible melanoma) unless it fits nicely into another category. And there really is nothing wrong with shaving melanocytic lesions. Although certain institutions don't do this, Dirk Elston and others have published plenty of evidence to support shave removals. We shave melanocytic lesions all the time.

 

[deltamed]

This is just one of several algorithms. The idea is to assume something is melanocytic (ig, a possible melanoma) unless it fits nicely into another category. And there really is nothing wrong with shaving melanocytic lesions. Although certain institutions don't do this, Dirk Elston and others have published plenty of evidence to support shave removals. We shave melanocytic lesions all the time.

Agree. I honestly am curious how other dermatologists manage to excise all suspicious melanocytic lesions. I consider myself pretty sparing in my biopsies of nevi (my ratio of melanoma to atypical/benign nevi sampled is about 1:4 or 1:5). But if I recommended an excision for all these probably half my patients would never return. So my opinion is they don't leave clinic without tissue in the formalin.

Really, its not a huge deal if you transect a melanoma especially if you always go at least 1-2 mm deep. It's not great form, but way better than missing them.

I would be curious to hear why others think excision is superior (beyond "because I trained that way or textbook said so")- I have an open mind.

 

[DermDudeMD]

Agree. I honestly am curious how other dermatologists manage to excise all suspicious melanocytic lesions. I consider myself pretty sparing in my biopsies of nevi (my ratio of melanoma to atypical/benign nevi sampled is about 1:4 or 1:5). But if I recommended an excisio

This is just one of several algorithms. The idea is to assume something is melanocytic (ig, a possible melanoma) unless it fits nicely into another category. And there really is nothing wrong with shaving melanocytic lesions. Although certain institutions don't do this, Dirk Elston and others have published plenty of evidence to support shave removals. We shave melanocytic lesions all the time.

n for all these probably half my patients would never return. So my opinion is they don't leave clinic without tissue in the formalin.

Really, its not a huge deal if you transect a melanoma especially if you always go at least 1-2 mm deep. It's not great form, but way better than missing them.

I would be curious to hear why others think excision is superior (beyond "because I trained that way or textbook said so")- I have an open mind.

Wow, thanks for that insight!

 

[DoctorDermis]

Prefer to Shave melanocytic lesions with a goal of obtaining all visible pigment in one go (unless large).
If the lesion turns out to be non-life threatening, then they are left with a round scar but no overall loss in tissue surface area.
If something is clinically suspicious for a malignant etiology, then will often perform an excisional biopsy

 

[deltamed]

Prefer to Shave melanocytic lesions with a goal of obtaining all visible pigment in one go (unless large).
If the lesion turns out to be non-life threatening, then they are left with a round scar but no overall loss in tissue surface area.
If something is clinically suspicious for a malignant etiology, then will often perform an excisional biopsy

I know what you are saying but the only real reason to biopsy a melanocytic lesion is if its "clinically suspicious for a malignant etiology." Maybe you mean an excision if you are almost "certain" it's melanoma?

I hate that so many of us just take off all mildly-looking atypical nevi. When a new patient comes to me that's had literally dozens of moles removed under the impression - wow my prior doctor "caught" all these atypical moles that could have hurt me - I cringe.

Not saying that's you. But we WAY over-treat atypical nevi (especially mild or mod- many patients probably half their moles are atypical).

 

[asmallchild]

I know what you are saying but the only real reason to biopsy a melanocytic lesion is if its "clinically suspicious for a malignant etiology." Maybe you mean an excision if you are almost "certain" it's melanoma?

I hate that so many of us just take off all mildly-looking atypical nevi. When a new patient comes to me that's had literally dozens of moles removed under the impression - wow my prior doctor "caught" all these atypical moles that could have hurt me - I cringe.

Not saying that's you. But we WAY over-treat atypical nevi (especially mild or mod- many patients probably half their moles are atypical).

Very strongly agree that we are over-treating atypical nevi.

As someone who gets referred the excisions on these biopsies, I wonder why they weren't excised to begin with? Most of the referrals I see appeared originally to be tiny nevi 2-4mm in size. To start off, I don't think the vast majority of these needed a biopsy.

But if one is going to biopsy it, why not take the 5 extra minutes to punch it out or excise it (especially if it's 2-4mm in size?!) rather than shave it, leave pigment behind (I can't tell you how many cases where the path signout is "margins appear clear" and pigment returns clinically months down the road), and subject the patient to yet another procedure (mind you, all for a lesion that I still don't believe is dangerous)?

 

[deltamed]

But why not take the 5 extra minutes to punch it out or excise it (especially if it's 2-4mm in size?!) rather than shave it, leave pigment behind (I can't tell you how many cases where the path signout is "margins appear clear" and pigment returns clinically months down the road), and subject the patient to yet another procedure (mind you, all for a lesion that I still don't believe is dangerous)?

Or why not take the 5 extra seconds to shave it correctly? If 2-4mm nevi are recurring after a shave you are either 1) not really intending to get it all or 2) very bad at controlling a dermablade 3) afraid of the scar which is silly since you were supposedly "worried" about the lesion and not doing the patient any good if it recurs.

I know many would disagree with me but I personally would be more confident getting the margins of an 8mm nevus with a shave than a punch. I almost never have to go back on atypical nevi except on severe, and often just cause the margins are close and the pathologist is nervous about it.

I knew an older dermatologist who literally never went back on atypical nevi regardless of grade of atypia, margins or pathologist "recommendation." If the comment was they couldn't rule out an early melanoma only then he would go back. I know it's anecdotal, but he didn't have a single disaster where the lesion later caused a bad clinical outcome. I'm not that ballsy, but its interesting....

 

[Tamahawk]

Always a fun debate.

As a Dermatopathologist, I can tell you that shave removals (with narrow margins) are easily better than punch biopsies for the vast majority of atypical melanocytic lesions, because histologic assessment of the periphery is CRITICAL for accurate diagnosis. Shaves more reliably than punches remove the entire lesion (especially for lesions 6mm in diameter or greater--which by the way is the typical size of most melanomas). Punches more commonly result in lesions abutting/approximating the peripheral edges, which limits your pathologist's ability to determine circumscription and ensure that there is not a lentiginous component trailing off at the edge (a bad feature). There are many studies that show that rates of peripheral transection are higher with punches than shaves, so this is not just a "I suck at punch biopsies" issue.

From a clinical perspective, I feel that shaves are superior because they are:
1) more practical than excision
2) do not result in any decrease in actionable information (compared with excision or punch), as long as the shave is >1mm in depth
3) they increase the Dermpath diagnostic accuracy for the reason mentioned up top
4) have a better chance at clearing the lesion and avoiding recurrence

 

[Tamahawk]

Regarding treatment of atypical nevi, the recent literature strongly supports that we are overtreating them...especially mild and moderates. The Mayo Clinic study showed that none of their mild or moderately dysplastic nevi extending to a margin (and that were NOT re-excised) developed into melanoma at the site, nor metastatic disease. Other studies have shown similarly reassuring findings. "Severely atypical nevi" should always be excised because there is a good chunk of these that melanocytic experts would actually say are misdiagnosed melanomas.

 

[deltamed]

Regarding treatment of atypical nevi, the recent literature strongly supports that we are overtreating them...especially mild and moderates. The Mayo Clinic study showed that none of their mild or moderately dysplastic nevi extending to a margin (and that were NOT re-excised) developed into melanoma at the site, nor metastatic disease. Other studies have shown similarly reassuring findings. "Severely atypical nevi" should always be excised because there is a good chunk of these that melanocytic experts would actually say are misdiagnosed melanomas.

Agree. I think the only plausible reason to go back on mild or moderate is that if it repigments, and they see another provider in the future who isn't sure whats going on, it may be re-biopsied and then possibly mis-called by another pathologist.

Better yet, do everything you can to not biopsy things that you arent suspicious for melanoma. The fewer atypical nevi you (mistakenly) biopsy the better.

 

[Decicco]

I still hear staff dermatologists talk about dysplastic nevi as if they are premalignant ("one day, this could turn into a melanoma!"). They pat themselves on the back when they remove a lesion and it comes back as moderately atypical (or worse, re-excise or re-shave these). Dysplastic nevi are benign. Melanoma is less likely to develop in a dysplastic nevus than in a regular nevus.

 

[deltamed]

I still hear staff dermatologists talk about dysplastic nevi as if they are premalignant ("one day, this could turn into a melanoma!"). They pat themselves on the back when they remove a lesion and it comes back as moderately atypical (or worse, re-excise or re-shave these). Dysplastic nevi are benign. Melanoma is less likely to develop in a dysplastic nevus than in a regular nevus.

Seems literature suggests the number of atypical nevi that might progress to melanoma is 1 : 10,000 or less. Can you please link articles to suggest this is less than a regular nevus?

I'm pretty sure most dermatologists are well aware of the low risk these lesions pose. I'm less convinced that some want to lose the revenue from excising these. Part of the problem is the disagreement between pathologists in certain cases between a particular atypical nevi and melanoma. In addition, the comment "excision is recommended" is way too common on path reports (often moderate atypia). I've had several pathologists tell me that if I stop going back on their "moderate" atypia they will just start calling them severe to make sure they are taken out. So the blame doesn't lie with just dermatologists and cover-your-as* medicine exists in both specialties (even with extremely low risks).

 

[Decicco]

Seems literature suggests the number of atypical nevi that might progress to melanoma is 1 : 10,000 or less. Can you please link articles to suggest this is less than a regular nevus?

I'm pretty sure most dermatologists are well aware of the low risk these lesions pose. I'm less convinced that some want to lose the revenue from excising these. Part of the problem is the disagreement between pathologists in certain cases between a particular atypical nevi and melanoma. In addition, the comment "excision is recommended" is way too common on path reports (often moderate atypia). I've had several pathologists tell me that if I stop going back on their "moderate" atypia they will just start calling them severe to make sure they are taken out. So the blame doesn't lie with just dermatologists and cover-your-as* medicine exists in both specialties (even with extremely low risks).

It is mentioned in a recent JAAD article: http://www.jaad.org/article/S0190-9622(15)01598-4/abstract

I can't believe that a pathologist would call something moderate atypia and then ask it be re-excised. I don't think the staff that I'm with are doing this to run up the bill, I think its a combination of genuine misunderstanding and worrying about lawyers.