Objective: To analyze the frequency and characteristics of enlarging common
melanocytic nevi.
Design: Cohort study using digital epiluminescence microscopy (ELM) for doc
umentation and follow-up, with a median follow-up interval of 11.4 months.
Setting: A dermatology department at a university hospital in Vienna, Austr
ia.
Patients: One thousand six hundred twelve melanocytic nevi appearing clinic
ally as common nevi, obtained from 385 patients (mean [+/-SD] age, 34.2 +/-
14.8 y; 55.6% female).
Interventions: Follow-up examination and documentation by digital ELM.
Main Outcome Measures: Frequency of enlarging nevi according to age and com
parison of ELM features observed in enlarging and nonenlarging nevi.
Results: Enlargement was found in 5.3% (n = 86) of nevi. The frequency of e
nlarging nevi was inversely related to age (P<.001), in that enlarging nevi
were common in pa -tients younger than 20 years and relatively rare in old
er age groups. Epiluminescence microscopy revealed a peripheral rim of brow
n globules in 48.8% (n = 42) of enlarging nevi. In contrast, a peripheral r
im of brown, globules was found in only 0.7% (n = 11) of nevi without enlar
gement (P<.001). Enlarging nevi that were excised in children and adolescen
ts showed no histological signs of atypia. Tn older age groups, 48.1% of ex
cised enlarging nevi that were clinically diagnosed as common nevi showed s
ome histological signs of atypia. None of the excised enlarging lesions was
histologically diagnosed as melanoma.
Conclusions: The frequency of enlarging common nevi is inversely related to
age. In the absence of clinical signs of atypia, enlargement alone does no
t indicate malignancy. A peripheral rim of brown globules is a characterist
ic ELM feature of symmetrically enlarging melanocytic nevi.