Linear Atrophoderma of Moulin: A Distinct Entity?

Abstract Linear atrophoderma of Moulin ( LAM ) is a rare dermatologic disorder characterized by a hyperpigmented atrophoderma that consistently follows the lines of B laschko. There are many clinical and histologic similarities between LAM , atrophoderma of P asini and P ierini ( APP ), and morphea, and whether LAM represents part of a disease spectrum or its own distinct entity is debated. This case of a 16‐year‐old boy with LAM supports the hypothesis that LAM , APP , and morphea are a spectrum of disorders rather than unique entities. Although the patient's overall clinical picture supports a diagnosis of LAM with hyperpigmented, depressed lesions following the lines of B laschko and perivascular lymphocytic infiltrate on biopsy, the bilateral presentation typical of APP , collagen entrapment of eccrine ducts typical of morphea, and changes in dermal collagen illustrate features spanning all three disorders, suggesting a relationship between these conditions that represents a spectrum of disease. Furthermore, a review of all reported cases of LAM in the literature suggests an evolving definition beyond what Moulin and colleagues originally described, including features related to those of APP and morphea.