A 6 year-old male patient was admitted to the dermatology department with an eruption on the right arm, chest and left leg. No clinical symptoms such as pain, pruritus or previous inflammation were present. His mother reported that the lesion had developed four years ago as small-sized hyperpigmented macules which enlarged in a short period of time as band-like hyperpigmentation, and then remained unchanged. His past medical history was unremarkable and there were no similar cases in the family.On physical examination, band-like hyperpigmented patches on the right arm were observed. A similar lesion was located on the right side. When the right shoulder was on horizontal adduction, lesions of chest and arm concurred in a large brown ring-like patch. Lesions on left leg showed the similar bandlike distribution with a darker brown color (figure 1). There were no signs of induration or sclerosis.Laboratory investigations included complete blood count, liver and kidney function tests, erythrocyte sedimentation rate, and antinuclear antibody test, which were negative or within the normal range.A skin biopsy was performed. Histological examination showed a normal epidermis outlined by a hyperpigmented basal layer. In the papillary dermis, vessels were surrounded by mild lymphocytic infiltrate and melanin-laden macrophages were present (figure 2).

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