Melanocytic naevus with severe melanocytic dysplasia

**Definition:** Melanocytic naevus with severe melanocytic dysplasia is a histopathological diagnosis based on the presence of severe cytological atypia, defined as enlarged, spindle- and epithelioid-shaped melanocytes with hyperchromatic nuclei (typically at least twice the size of those of basal keratinocytes) and distinct nucleoli. Such naevi tend to be irregular in size and pigmentation and to have been excised because of concern that they may represent early melanoma.