Case Number : Case 2962 - 12 November 2021 Posted By: Dr. Richard Carr

Looks dysplastic, maybe severe with some superficial regressive changes and patchy early pagetoid spread. I don't think it's enough for me to go to MMIS/MM but it might be on its way there.

1 hour ago, sfwenson said:

Looks dysplastic, maybe severe with some superficial regressive changes and patchy early pagetoid spread. I don't think it's enough for me to go to MMIS/MM but it might be on its way there.

Agree. The sovrapapillary epidermal plate is often infiltration-free. So my conclusion is: confluence ( so important in melanoma ) is missing.

Looks like Dysplastic nevus. MelanA shows some confluence but I agreee with Vicenzo and Sfwenson that it is not enough to call it insitu. I would like to see a sox10 just to be sure.

Agree with dysplastic nevus. PRAME is not expressed, no loss of p16 also not supportive of melanoma.

I favoured a challenging, dysplastic, slightly spitzoid, naevus (Clark & Spitz = SPARK). Agree p16 and PRAME appear to support the diagnosis. I've found the PRAME was supportive of a favoured diagnosis in 87% of cases now (39/45 supporting my favoured diagnosis, limiting to cases in which I was not on the middle of the fence). I'm now using PRAME routinely in challenging cases and it's good to assess for pre-existing naevi, Breslow measurement, growth phase and margins assessments with some caveats. 

Forgot to say well done on the excellent responses. Sometimes it's difficult not to call everything challenging or difficult melanoma by default although I think we should have robust criteria for melanoma and when we don't have a diagnostic lesion I think admitting uncertainty is key and making sure the lesion is out with a clear margin whenever possible.