Malignant melanoma Breslow's 0.6 mm, with regression 

When you look at a red octagonal street sign, you immediately know what it is and what it signifies.  The same should apply any time you see a lesion like this.  Not many things scare me.  I'm not afraid of spiders, snakes, or heights but I am afraid of anything that looks like this.  The thundercloud gray to pink look in the center of what can only be a melanoma means only one thing:  Regression.  

As you know, regression means that the lymph node has already gotten a taste of the melanoma, even though it is not very thick, and the lymph node then mounted an attack on the primary lesion.  Even in the case of a non-palpable node, it is a metastatic problem  from the moment regression is evident.  Will the metastasis kill the patient?  Maybe, maybe not, but nevertheless it is there.

All of you recognized this was a melanoma, but if you did not mention regression, you did not get full credit for this answer.  When you see a lesion like this, check their nodes and think about SLNBx and heme-onc referral.