Pseudomelanoma. Una difficile diagnosi dermatoscopica

Some pigmented skin lesions such as some Clark's and Spitz's nevi may show diagnostic difficulties by means of epiluminescence microscopy pattern analysis and ABCD rule of dermatoscopy. Three cases of pseudomelanoma (persistent/recurrent melanocytic nevus) misdiagnosed as melanoma using the two methods of dermatoscopic analysis are reported. The correct diagnosis was possible only by the evaluation of anamnestic data revealing previous surgical treatments or accidental trauma of the lesions. These events provoked morphologic alteration of the dermo-epidermal pigmented structures as well as the formation of cicatricial tissue which rendered the dermatoscopic diagnosis not possible. Therefore, due to the difficulties in clinical and dermatoscopic interpretations of pseudomelanomas, the histologic examination cannot be avoided in such cases.