Background: Dysplastic nevi are markers of melanoma risk and potential
precursors of melanoma. Few studies have addressed the natural histor
y of dysplastic nevi. Objective: Our purpose was to describe the chang
es observed in nevi over time in a cohort of our patients with dysplas
tic nevi. Methods: We used a historical cohort design to study 153 pat
ients with dysplastic nevi observed for a minimum of 5 years. Physical
examination at completion of the study was compared with baseline ove
rview and close-up photographs. Lesions excised during the study inter
val were assessed for history of change. Results: Fifty one percent of
all evaluated nevi (297 of 593) showed clinical signs of change durin
g an average follow-up of 89 months. New nevi were common in adulthood
and continued to form in more than 20% of patients older than 50 year
s of age. Nevi were observed to become more clinically atypical, less
clinically atypical, and disappear in all age groups. In this small co
hort rates of nevus change were not correlated with personal or family
history of melanoma, sex, or total number of nevi. Total nevus counts
and rates of nevus change were correlated with age. Conclusion: Dyspl
astic nevi remain clinically dynamic in adulthood. Our data suggest th
at the decrease in counts of dysplastic nevi associated with increasin
g age is only partly explained by the disappearance of nevi over time
and probably reflects a tendency to larger numbers of nevi among more
recent birth cohorts.