ABSTRACT
In dermatology, the term ‘nevus’ does not refer to a specific entity but to many different ones that have been defined as ‘circumscribed developmental lesions of skin or mucous membrane involving excess or deficiency of any one of the normal structures’.1 Many authors regard a non-neoplastic nature as a prerequisite.2 However, the term ‘nevus’ has long been in use in a less restricted way, and without further qualifications it generally refers to a small, selflimiting proliferation of cutaneous melanocytes, which is neoplastic in nature. The most common form of this latter entity, the common acquired melanocytic nevus, and its variants constitute the subject of this chapter. For a general discussion of the use of the term ‘nevus’ in dermatology, the reader is referred to a review by Happle.3 In the present text, which deals with melanocytic disorders, we shall refer to ‘nevi’ only to indicate melanocytic nevi.
