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.