Atrophoderma of moulin with preceding inflammation

A 16-year-old Vietnamese man presented to the Dermatology Clinic with a 10-year history of bizarre brown patches, which initially started as red asymptomatic "bumps" on the trunk, upper and lower extremities, and face. His past medical history was significant for hypothyroidism and idiopathic urticaria. He was on Eltroxin for hypothyroidism. The family history was noncontributory. Physical examination revealed two types of lesion: erythematous, well-circumscribed papules in a linear configuration along with linear hyperpigmented atrophic patches following Blaschko's lines were noted on the lower extremities (Fig. 1), right upper extremity, right flank (Fig. 2), and right jawline. Initial biopsies taken from the papular lesions on the right thigh and right elbow revealed the following changes. The first biopsy showed a slightly thinned epidermis with prominent dilated blood vessels in the superficial dermis. There also appeared to be a slight increase in the amount of collagen in the deep dermis. The findings were reported as in keeping with "epithelial atrophy." The second biopsy from the lesion on the right elbow revealed an acanthotic epidermis. The granular layer was absent in several areas and there was marked overlying parakeratosis. In the dermis, there was a heavy perivascular lymphocytic infiltrate. The appearances were consistent with a psoriasiform dermatitis (Fig. 3). A biopsy taken from the left thigh approximately 18 months later showed slight irregular acanthosis with dermal edema, dilated blood vessels, and a patchy lymphocytic infiltrate. The appearances were compatible with mild inflammation.