Atypical Spitz tumour: a 'chameleon' lesion.

It is a common experience that many Spitz naevi deviate from the idealized or stereotypical representation found in the literature, often causing considerable difficulties in distinguishing them from melanoma. The diagnostic term 'atypical Spitz naevus' is used to describe lesions that deviate from the typical appearance of Spitz naevi and which have an uncertain biological significance and prognosis. The term 'Spitz tumour' has been proposed for these lesions, as the term 'naevus' indicates a lesion that is completely benign and presents no risk to the patient. We present a case of atypical Spitz tumour with peculiar atypical clinical and dermatoscopic features. The difficulty in managing this Spitz tumour was aggravated by the clinical diagnosis. In fact, the lesion appeared as a benign and nonmelanocytic lesion, a pigmented dermatofibroma. Our case underlines the difficulties present in the controversial chapter of spitzoid melanocytic lesions. The atypical Spitz tumour is a 'chameleon' lesion that can mimic not only melanocytic, but also nonmelanocytic lesions.