Dermoscopic changes in acral melanocytic nevi during digital follow-up

Objective: To investigate changes in dermoscopic patterns of acquired acral melanocytic nevi (AAMN) over time. Design: Retrospective analysis of digital dermoscopic follow-up of 230 AAMN located on acral volar skin. Setting: Outpatient clinics at university dermatology departments. Patients: A total of 230 AAMN located on the soles (n = 149), fingers (n = 62), and palms (n = 19), of 230 white subjects 14 years or younger (n = 81), 15 to 30 years (n = 72), and older than 30 years (n = 77). Main Outcome Measure: Comparison of baseline and follow-up dermoscopic patterns. Results: Individual AAMN had a digital follow-up of 6 months (n = 59), 12 months (n = 74), 18 months (n = 44), and 24 months (n = 53). Baseline dermoscopic images showed the following patterns: parallel furrow (48.8%), latticelike (16.1%), fibrillar (10.9%), nontypical (10.9%), homogeneous (4.8%), globular (3.5%), transition (3.5%), and reticular (2.6%). Dermoscopic changes over time were observed in 42 of the 230 AAMN (18.3%), with the greatest frequency of changes occurring in patients 14 years or younger (23 of 81 lesions; 28.4%) (P = .005). The parallel furrow pattern (25.9%) showed more variations over time than other dermoscopic patterns (11.0%) (P = .004). The frequency of change increased linearly over time (P = .001). Four of 7 clinically regressing nevi showed a homogeneous pattern at the last examination. Conclusions: Dermoscopic changes of AAMN are most common in subjects younger than 14 years. The parallel furrow pattern appears to be the dermoscopic pattern most subject to change, while the homogeneous pattern may be seen also in AAMN showing clinical and dermoscopic involution.