Excision Margins

[DrSwede]

1st year med student here, so I hope I'm not intruding. I've been given an article to review, but I need answers to basic questions.

In the article, the path report for a patient states that they have a thin melanoma with a tumor thickness of .91mm and the guidelines for surgical excision margins state that 1-cm margins are appropriate for this melanoma.

So my problem is that I've never seen any biopsies performed nor any surgical excisions, therefore I'm not sure when they state "1-cm margin" if it means:

1. cutting down to the epidermis to a depth of 1 cm

Or

2. cutting a circle around the melanoma with a diameter of 1cm (in the hopes of getting normal tissue)

Or

3. I believe in the case of Mohs, you take horizontal sections and go deep.

With regards to the article, this excision is used for removal and not identification, so I'm not sure if that makes a difference or not. EDIT: Just wanted to state that the Clark level is IV.

Thanks for any help!

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[Long Dong]

2. cutting a circle around the melanoma with a diameter of 1cm

I've been in on one meloanoma excision as a 4th year med student and that is what they did.

 

[MOHS_01]

1st year med student here, so I hope I'm not intruding. I've been given an article to review, but I need answers to basic questions.

In the article, the path report for a patient states that they have a thin melanoma with a tumor thickness of .91mm and the guidelines for surgical excision margins state that 1-cm margins are appropriate for this melanoma.

So my problem is that I've never seen any biopsies performed nor any surgical excisions, therefore I'm not sure when they state "1-cm margin" if it means:

1. cutting down to the epidermis to a depth of 1 cm

Or

2. cutting a circle around the melanoma with a diameter of 1cm (in the hopes of getting normal tissue)

Or

3. I believe in the case of Mohs, you take horizontal sections and go deep.

With regards to the article, this excision is used for removal and not identification, so I'm not sure if that makes a difference or not. EDIT: Just wanted to state that the Clark level is IV.

Thanks for any help!

No problem, continue to ask questions whenever you have them for that is an efficient learning tool.

Surgical margins, for melanoma, are determined by the depth of invasion (Breslow's depth), which is measured from the granular layer to the deepest appreciated tumor invasion. For the 0.91mm tumor described, assuming that the biopsy was adequate to determine depth, a 1cm margin is what is currently recommended. This means that you mark the clinically apparent margins of the tumor and measure out 1cm in all directions. Depth of excision is a matter of some debate, but most still advocate full thickness excision down to fascia where plausible.

(Mohs) micrographic surgery is not currently accepted as "standard of care" for invasive melanoma, so most will not perform it on such cases. It's not purely horizontal sectioning, either -- tangential is probably a better descriptor. The lateral margins are processed in a vertical fashion, while the depths are processed in more of a horizontal fashion.

Hope that this helps.

 

[DrSwede]

Another question:

In the article, the patient ended up having her axillary lymph nodes excised after her sentinel node biopsy came back with one positive node.

So, what kind of physician performs sentinel node biopsy and the axillary node excision? (General Surgeon?)

 

[MOHS_01]

Yes, here in the States a general surgeon would be the most likely person performing SLN and nodal dissection. In Europe those crazy dermies do their own nodal dissections. I'm glad that I live here.

 

[goodies]

a "surgical oncologist" specifically usually does it... at least at my school...

 

[SDN9876]

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[mike1618]

I have to say that this is a very refreshing thread. I have been browsing the Derm forum for quite some time now looking for any interesting information. For the most part, this forum has been nothing but pre-meds wanting to know how much they can potentially make.

Thanks to the OP as well as those that gave their time to answer the questions. This sort of thread is very informative.