"Stuck on" appearance meaning

[Vanity]

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I am not a native English speaker. Inread Toronto Notes and there is this sentence in clinical presentation of Seborrheic Keratosis : "well demarcated waxy papule/plaque with classic 'stuck on' appearance".
What I know from 'stuck on' is that it means attached, but I don't think the meaning makes sense in this sentence.
Can anyone please explain what does 'stuck on appearance' mean?

Thank you

 

[adrenergic91]

It looks like it doesn't belong on your body, like someone stuck it on you, or like you have a bug on your skin or whatever.