Hyperpigmented patches following blaschko lines: Two probable cases of linear atrophoderma of moulin with subtle atrophy and a critical review of the subject

Abstract

Linear atrophoderma of Moulin (LAM) is a rare clinical entity characterized by hyperpigmented, depressed band-like skin lesions following blaschko lines (BL). Since its first description by Moulin et al., several authors have presented cases with variable clinical and histopathological features and have diagnosed them as LAM. Whether all those cases represented classical LAM as described by Moulin et al. or they represented a related dermatosis; depends on whether we confine the diagnosis of LAM as presented by Moulin et al. or consider it to be a spectrum where lesions may have overlapping clinical and histopathological findings. Some dermatoses that follow BL and have overlapping clinical and histopathological findings include LAM, idiopathic atrophoderma of Pasini and Pierini and Blaschkolinear morphea. Thus, it becomes difficult for a physician to diagnose these conditions when their typical clinical and histopathological findings are not present, especially when they present in early stages of evolution. Here in, we present two cases of LAM where the visible clinical atrophy is mild in one and not appreciable in the other. Whether our cases are the genuine cases of LAM or represent a stage of LAM or fall in the spectrum of LAM depends on how we expand the definition of LAM. We believe that whenever there is an encounter with hyperpigmented lesions in a blaschkoid pattern, a long-term follow-up is needed with serial biopsies to make a final definitive diagnosis.