Regression of Atypical Nevus: An Anecdotal Dermoscopic Observation

BACKGROUND Clark nevi (atypical melanocytic nevi) can be considered as risk markers and potential precursors of melanoma. The authors report on the morphologic changes of an atypical nevus by dermoscopic follow-up examination over a 7-year period. CASE REPORT A 43-year-old man had a brown macule on his back, sized 5 mm, with an irregular shape, clinically and dermoscopically diagnosed as an equivocal melanocytic lesion. Dermoscopically during the initial examination, a predominant reticular pattern with peripheral eccentric hyperpigmentation in the lower portion of the lesion could be seen. After 7 months, the area of peripheral eccentric hyperpigmentation had regressed, and after 4.5 years the atypical pigment network had almost disappeared. After 7 years of follow-up, a diffuse area of hypopigmentation and a residual light brown pigmentation were detectable. The histopathologic diagnosis was consistent with an atypical junctional nevus with regression with features of a Clark nevus. CONCLUSION Based on our observation, even a dermoscopically atypical nevus may undergo regression as documented by long-term dermoscopic follow-up.