Ok, I called the LE agency per NamUS contact:
The LE agency confirmed to me that hospital doctors diagnosed the scar as vitiligo. They didn't mention it in NamUS because they wanted the next of kin give this kind of detail for a match.
I kindly replied to him that even if I don't know him and can't say who is he, it was obvious only by looking at the scar that it's vitiligo because my friend's daughter has it too.
So, you don't need to specifically know the person to see that the scar/mark is vitiligo, at least when you've known a person with vitiligo.
He thanked me for this piece of information. He thought that only people who know him could recognise the scar as vitiligo. Not quite!
So, vitiligo has been confirmed by LE agency.
Which is a very valuable clue for finding a potential match.