An asymptomatic well-defined brown coloured plaque on the eyebrow in a middle aged woman

On january 2012, we visited a 48-year-old woman for her skin lesion on the left eyebrow. it had been appeared as an asymptomatic lesion with gradual enlargement since 2 years ago. there was no family history of a similar lesion. no drug was used by the patient. physical examination revealed a nearly 1 cm, dark brown, non-ulcerated, oval shaped plaque on the distal part of the left eyebrow. the inferior medial part of the lesion was lighter in color. on palpation, the periphery of the lesion was flattened and the centre was elevated (figure 1).we took a 3 mm punch biopsy from the lesion.