Dysplastic Junctional lentiginous nevus

I am seeing more and more lesions on the back and face of chronically sun damaged individuals reported as lentiginous junctional dysplastic nevus. The first case below has had several shaved off his back and this one on his chest wall. It has recurred. The others have not.

Case 1 This lesion has arisen on the anterior chest wall in the area where a lentiginous dysplastic junctional nevus was shaved 5 years ago but not re excised. At the time the shave was reported to have cleared the lesion. Do you always re excise these lesions with ?5mm margins.  Many of them are large and on the face. What do you think this lesion will be reported as now? The first two images are the original lesion and dermatoscopy- I do not have the histology.

Latest images

Case 1 fg 4845

Case 2 Lesion on shoulder. This was noted in an elderly male on a routine skin check. Is this going to be another Lentiginous dysplastic junctional nevus or will it be reported as a melanoma or something else? The pigmented lesion laterally was a seb k.

Case Two 4675

Dr Ian McColl said...
Tim I agree with what you say. In the last 5 years we now understand that LJDN really are melanoma in situ. When you then add 5mm margins most of these require an excision and flap repair if on the face and a very big ellipse on the back. I think with the way these are now reported by some eminent pathologists as melanoma that we should excise then appropriately and charge Medicare for excision of melanoma. It would help if pathologists reported uniformly on these lesions.

10:47 AM
Dr Ian McColl said...
Conny, you correctly raise the issue of recurrences in a shaved area and how the previous surgery may distort the pathology. I will put the pathology up later but from memory there was not much scarring seen.

Dr Ian McColl said...
Case 1 was reported this time as insitu melanoma fully excised but with a lot of regression!

Dr Ian McColl said...
I have put up the histology of case 2. Less impressive than case 1 However this was reported as Level 2 melanoma , Breslow 0.38 with features of both lentigo maligna and superficial spreading melanoma.

Graeme Siggs said...
Jeff,
The article which Peter B. refers to by John Zitelli's group in Pittsburgh comparing 6mm to 9mm margins for LM/MIS was in JAAD recently
J Am Acad Dermatol 2012;66:438-44.

Here's the link to the abstract:

http://www.eblue.org/article/S0190-9622%2811%2900697-9/abstract

I know it was in a tertiary referral centre, but MIS is MIS wherever it's treated!


Background: A controversy in the treatment of melanoma in situ is the required width of surgical margin.
The currently accepted 5-mm margin is based on a 1992 consensus opinion, despite data since then
showing this is inadequate.

Objective: We sought to develop guidelines for predetermined surgical margins for excision of melanoma
in situ.

Methods: A prospectively collected series of 1072 patients with 1120 melanoma in situs was studied. All
lesions were excised by Mohs micrographic surgery with frozen-section examination of the margin. The minimal surgical margin was 6 mm, and the total margin was calculated by adding an additional 3 mm for each subsequent stage required. The minimum surgical margin that would successfully remove 97% of all tumors was calculated. Local recurrence was also tabulated.

Results: In all, 86% of melanoma in situs were successfully excised with a 6-mm margin; 9 mm removed
98.9% of melanoma in situs. The superiority of 9-mm to 6-mm margins was significant (P <0.001). Recurrence rate for this set of patients treated with Mohs
micrographic surgery was 0.3% (n = 3).

Conclusion: The frequently recommended 5-mm margin for melanoma is inadequate. Standard surgical excision of melanoma in situ should include 9 mm of normal-appearing skin, similar to that recommended for early invasive melanoma

Dr Jeff Keir said...
I know the paper, graham - it just doesn't correspond with the reality as I see it in my practice and about 500 mm over the last 10 years.

Is mmis, mmis? There are very reasonable doubts about the use of Mohs for LM in any case

Ian Katz said...
Both are melanomas histologically.

Never believe margins on shaves - how can one?

Never do frozens for melanocytic lesions - what a minefield...

That paper on Mohs margins for melanomas probably just confirms what we all know. Some patients with 5mm margins need wider excisions. It is what we do all the time. It does not mean that we need to do 9mm margins on all to start just so we do not have to go back on 98%