Rapid, severe repigmentation of congenital melanocytic naevi after curettage and dermabrasion: Histological features

Background: Curettage and dermabrasion are effective in treating giant congenital melanocytic naevi (GCMN). We report two patients with rapid, severe postoperative repigmentation. To the best of our knowledge this is the first report on the histological features of such patients. Objectives: We wish to call attention to histological features that may cause rapid, severe repigmentation after curettage and dermabrasion of medium to giant CMN. Patients/methods: From 1998 to 2002, we treated 23 patients with medium to giant CMN with curettage and dermabrasion. Patients being treated ranged in age from 1 month to 19 years. Histological samples were taken from the centre of naevi in all patients during surgery. Histological types were 12 intradermal and 11 compound. Follow-up after curettage lasted at least 3 years. Results: Among our 23 patients only two showed repigmentation soon after surgery. Histological sections from these two patients indicated naevoid cells in the deep dermis along hair follicles or sebaceous glands. However, no such pigmented naevoid cells along hair follicles were observed in samples from patients successfully treated with curettage and dermabrasion with less repigmentation. Conclusions: Although we saw only two cases of repigmentation soon after curettage and dermabrasion, we suspect a correlation between pigmented naevoid cells around hair follicles and repigmentation. If histological sections of skin biopsies show pigmented cells along hair follicles in the deep dermis, other treatments such as total skin resection followed by skin grafting or tissue expansion may be better choices than curettage or dermabrasion.