Melanoma is never "featureless".
Helm
Thomas N
TN
D006801:Humans; D008545:Melanoma / Q000175:diagnosis* / Q000473:pathology; D018328:Melanoma, Amelanotic / Q000175:diagnosis / Q000473:pathology; D008853:Microscopy; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology