In situ amelanotic melanoma of the nail unit mimicking lichen planus: report of 3 cases.

Background: Nail apparatus melanoma is known to be associated with a poor prognosis, mainly because of a delay in diagnosis that is made at an invasive stage. This delay is particularly true in cases involving amelanotic melanoma. To our knowledge, only 1 case of in situ amelanotic melanoma of the nail unit has previously been described.

Acantholytic tumor of the nail: acantholytic dyskeratotic acanthoma.

Acantholytic dyskeratotic acanthomas of the skin have been recently described in several publications. They differ from acantholytic acanthomas by the presence of dyskeratosis. However these tumors have never been described in nails.