Dermoscopic and Immunohistochemical Changes in Acquired Melanocytic Nevi following Narrow-Band Ultraviolet B Therapy

Abstract

Background: Acquired melanocytic nevi (AMN) have been reported to undergo morphological and dermoscopic changes following exposure to narrow-band ultraviolet B (NB-UVB) radiation. Objective: To study the morphological, dermoscopic and immunohistochemical changes in AMN following NB-UVB radiation. Methods: Suberythemogenic NB-UVB sessions were delivered to 40 patients with AMN. For each patient, a minimum of 2 nevi were selected. One nevus was surgically removed from each patient prior to sessions as control; for the other nevus, dermoscopic images were captured before and after NB-UVB sessions. The images were evaluated for changes. At the end, another nevus was surgically removed for immunohistochemical assessment of Ki-67 and melan-A. Results: Our study showed a statistically significant increase in the size of AMN following NB-UVB radiation. Benign dermoscopic changes were observed. Statistically significant positive correlations were found between some dermoscopic findings and the total cumulative dose of NB-UVB. Immunohistochemical analysis did not show any significant change in the exposed AMN. Conclusion: AMN irradiated with repeated suberythemogenic doses of NB-UVB showed benign morphological and dermoscopic changes, and this was confirmed by our immunohistochemical study.