Melanoma vs Nevus: Microscopic Clues for Malignancy Explained in 5 Minutes 

Great questions that I wish he answered!!

​@@speaklifegardenhomesteadpe8783 Dysplastic nevus vs melanoma can be tricky but is usually mostly bssed off of histology. And even then, dysplastic nevus is graded as mild, moderate and severe. There is a lot of inter-observer variability between the two entities.

It’s a bit complicated. If epidermis is missing just due to unzipping artifact, then I would not call it ulcerated. If totally absent epidermis and I think it’s artifactual I would probably say for ulceration “cannot assess” with a comment that the epidermis is missing and it appears to be artifactual but because of this I can’t determine if true ulcer or not. If it’s truly ulcerated (fibrin and neutrophils on surface favor ulcer, clean surface favors artifact but sometimes hard to be certain) and the epidermisis absent due to that then I would call it ulcerated. In both cases I would measure the breslow from the area where the epidermis used to be (ie ulcer base or unzipped area) down to deepest point of invasion. My general rule is I try to give the required prognostic parameters for melanoma by the AJCC book. But Sometimes cases don’t fit neatly or follow the rules. In those cases I just give the information as best I can and say uncertain or cannot assess for any feature that I’m not able to give an accurate result for. And then I add a comment explaining why I was not able to give that data point. Hope that helps a little bit.