Paul Gerson Unna's Abtropfung theory that nevi develop through migration of nevus cells from the epidermis to the dermis prevailed for almost a century until the Hochsteigerung theory postulated the reverse pattern of migration based on newly acquired observations from histopathology and studies of embryogenesis. Most recently, however, new insights gained from epidemiology, cross-sectional and longitudinal studies of nevi, dermoscopy and confocal microscopy, and cellular and molecular studies have brought into question both of the aforementioned theories. This book provides a comprehensive guide to current knowledge about nevogenesis by presenting these latest advances and in addition discusses issues yet to be resolved. It will assist practicing physicians in effectively managing patients with a variety of nevi and will also be of great value to researchers in the field. Importantly, since nevi are associated with an increased risk of melanoma, understanding nevogenesis may help to unravel some of the mysteries of melanomagenesis.

1 Nevogenesis: Changing Theories ................................................ 1
Mark E. Burnett, Alon Scope, and Ashfaq A. Marghoob
2 Classifying Melanocytic Nevi ...................................................... 25
Iris Zalaudek, Caterina Longo, Cinzia Ricci, Giuseppe Albertini,
and Giuseppe Argenziano
3 Evolution of Nevi .......................................................................... 43
Harald Kittler
4 The Dual Pathway of Nevogenesis .............................................. 49
Iris Zalaudek, Alon Scope, Giuseppe Argenziano,
Caterina Longo, Simonetta Piana, Caterina Carticalà,
and Ashfaq A. Marghoob
5 Confocal Microscopy: Improving Our
Understanding of Nevogenesis .................................................... 59
Barbara De Pace, Barbara Ferrari, Barbara Predieri,
Lorenzo Iughetti, Leonardo Veneziano, Iris Zalaudek,
Giuseppe Argenziano, Caterina Longo, and Giovanni Pellacani
6 Nevi in Children and Adults: Dermoscopic Patterns
and the Development of New Nevi .............................................. 69
Tracey Liebman, Natalia Jaimes Lopez, and Stephen W. Dusza
7 Etiology of Congenital Melanocytic Nevi
and Related Conditions ............................................................... 73
Miguel Reyes-Múgica, Mark Beckwith, and Heather C. Etchevers
8 Molecular Nevogenesis: An Update............................................ 99
Andrew L. Ross, Margaret I. Sanchez, and James M. Grichnik
9 Nevogenesis: A Benign Metastatic Process?: An Update ......... 111
Andrew L. Ross, Margaret I. Sanchez, and James M. Grichnik
10 Nevus Senescence: An Update .................................................... 117
Andrew L. Ross, Margaret I. Sanchez, and James M. Grichnik
11 Genes and Nevogenesis ................................................................ 127
Stephen W. Dusza and Mark E. Burnett
viii Contents
12 Malignant Transformation of Melanocytic Nevi ....................... 137
Alexander Marzuka-Alcalá and Hensin Tsao
13 Disappearance of Melanocytic Nevi ........................................... 145
Vitaly Terushkin, Alon Scope, Rainer Hofmann-Wellenhof,
and Ashfaq A. Marghoob
Index ...................................................................................................... 155