Cutaneous melanoma with pseudomyxoid features.

A 96-year-old man presented with a polypoid melanoma, which showed a prominent clear stroma, similar to that of myxoid melanoma, but stained negative for Alcian blue at pH 2.5 and for colloidal iron. It is not clear whether melanoma displaying pseudomyxoid features (pseudomyxoid melanoma) may represent a distinct histological variant of melanoma. However, it must be differentiated from true myxoid melanomas, in which Alcian blue-positive acid mucopolysaccharides are present. Urso C. Cutaneous melanoma with pseudomyxoid features.