A woman in her early 20s presented with 1 year of discrete asymptomatic brown lesions distributed over her lower extremities. She denied any history of trauma or prior lesions at these sites and could not pinpoint any exacerbating or alleviating factors. She denied fever, arthralgias, myalgias, or constitutional symptoms. She had no significant past medical history and took no medications or supplements. A physical examination revealed several 2-mm to 4-mm round, hyperpigmented macules symmetrically distributed over the lower extremities and dorsal feet (Figure, A). No prior treatments had been attempted. A skin biopsy was performed (Figure, B-D). What is your diagnosis?
Awan SZ, Finch J, Kristjansson A. An Asymptomatic Hyperpigmented Eruption on the Lower Extremities. JAMA Dermatol. Published online March 15, 2017. doi:10.1001/jamadermatol.2017.0112