Spitzoid tumour of uncertain malignant potential

**Definition:** A spindle cell and epithelioid cell melanocytic neoplasm in which there are sufficient features distinguishing it from a benign Spitz naevus to cast doubt on its benign nature. These atypical features include development in adult life, asymmetry, large diameter (>6 and especially >10 mm), significant thickness (particularly subcutaneous extension), lack of “maturation” and nodule formation, cytological atypia and a high mitotic rate.