Well, there is something called a seborrheic keratosis - usually looks kind of greasy or scaly, somewhat irregular and "stuck on" looking. They are benign (non-cancerous) and can sometimes be picked off. So it is possible that is what is was.
But that is a pretty common thing and his physician ought to have been able to diagnose it by looking at it. Did they actually tell him they thought it was cancerous? Had they biopsied it before?
Of course, sometimes it can be hard to tell and they want to send it to pathology when they remove it just to be sure that is all it was.
My guess is, if they never had a firm idea that it was cancer, and the skin underneath is now smooth and normal, then it might have been a seborrheic keratosis. Any way you could just talk to his doctor about it yourself? (They wouldn't talk to you in the States, but I bet where you live the rules are more liberal.)
