Spitz tumours

The traditional dichotomous classification of Spitz naevus versus Spitzoid melanoma is challenged by a group of lesions that deviates from the prototypic Spitz naevus; these lesions (Spitzoid tumours of uncertain malignant potential [STUMP]) remain difficult to define using objective criteria. Clinical series and comparative molecular genetic studies support the concept that Spitzoid lesions form a family of melanocytic tumours distinct from ordinary naevi and common types of melanoma. A bipolar classification of naevus versus melanoma does not readily accommodate the recognized diverse spectrum of pathological features and behaviour observed in Spitz lesions and it has been proposed that they be viewed as part of a continuum with significant modification of the current terminology. These proposals remain controversial.