First of all could I compliment Richard Carr on the beautiful presentation and annotation of these slides.

I can see that no-one wishes to venture an opinion on these slides.  i suspect that this is partly because, like me, colleagues have little or no experience of interpreting longitudinal biopsies of the nail apparatus.

There is evidence of a variable pattern of melanocytic proliferation, showing both junctional, lentiginous and Pagetoid growth patterns.  The cytology is not particularly alarming, although there is evidence of mitotic activity.  More than that, I don't really know how to interpret these findings and look forward to being enlightened.

Sorry i had issues with accessing the website. something went wrong

i can see pagetoid spread and i suspect it is melanoma.

Acral type nevus. 

Looks like Spitz nevus on acral skin, however the loss of p16 expression points towards acral melanoma. Can we know how large was the 1st lesion?

Great presentation! nails trouble be alot

Interesting read:

Acral Spitz Nevi: A Clinicopathologic Study of 50 Cases With Immunohistochemical Analysis of P16 and P21 Expression

Ok! Now, I would read some other expert comment ( the msofopoulos is one of them ). Maybe I’m wrong. 

The previous biopsy was reported to be melanoma in situ. I agreed with residual melanoma in situ matrix and a focus of melanoma at the distal finger (p16 loss and high Ki67 in addition to PRAME were clearly indicative of melanoma for me). There were scattered PRAME positive cells in nail bed too so I assume it was all connected. As you know for acral and nail lesions the melanocytes can travel some distance in the skin as subtle, pauci-cellular disease which can give rise to a high rate of local recurrence. The aggressiveness of the surgery needs to be balanced against the potential loss of function. Most thin lesions like this can be treated with complete resection of nail apparatus and skin grafting for the defect without resorting to amputation but obviously patients should be closely monitored for local recurrence. It seems PRAME may be an adjunct to assessing acral lesions and also margins although larger studies will be required.

Great case, Thanks. 

On 17/10/2021 at 13:10, vincenzo said:

Ok! Now, I would read some other expert comment ( the msofopoulos is one of them ). Maybe I’m wrong. 

I am not an expert. I would like to know in acral MIS what is considered (in your country) to be safe/clear margin. In Greece there are no guidelines regarding that.

Again great case and  great explanation " acral and nail lesions the melanocytes can travel some distance in the skin as subtle, pauci-cellular disease which can give rise to a high rate of local recurrence" is gold

6 hours ago, msofopoulos said:

I am not an expert. I would like to know in acral MIS what is considered (in your country) to be safe/clear margin. In Greece there are no guidelines regarding that.

Again great case and  great explanation " acral and nail lesions the melanocytes can travel some distance in the skin as subtle, pauci-cellular disease which can give rise to a high rate of local recurrence" is gold

5 mm for MIS in acral sites ( fingers ). But 3 mm in first excision can be enough, with close monitoring of thew patient, of course. 

On 24/10/2021 at 00:28, vincenzo said:

5 mm for MIS in acral sites

Thanks Vincenzo