Linear atrophoderma of moulin: report of 4 cases and 20th anniversary case review

Background: Linear atrophoderma of Moulin (LAM) is a rare clinical entity which was first described by Moulin et al. in 1992. The diagnosis is clinical, characterized by acquired unilateral hyperpigmented, depressed band-like skin lesions following Blaschko's lines. The disease typically affects children or adolescents and has a good prognosis without evidence of long-term progression. To date, the pathophysiology is unclear. Different authors hypothesize that the disease is secondary to a mosaic manifestation as a result of a post-zygotic mutational event. Observations: Four patients (2 men, 2 women) had a history of unilateral band-like skin lesions located on the lower legs (50%) or the trunk (50%). Physical examination showed atrophic and hyperpigmented skin lesions along Blaschko's lines, which appeared during childhood in 3 cases and at the age of 20 in the last case. Lesions had progressed rapidly but seemed to have stabilized so far except for 1 case who presented spontaneous improvement. Histopathological examination revealed a normal epidermis with a hyperpigmented basal layer and a perivascular lymphocytic infiltrate in the dermis. Conclusion: LAM is a rare disease with 32 reported cases and remains an exclusion diagnosis. Since the problem is mainly esthetic, treatments should not be too aggressive.