A dark lesion with a predominant globular pattern

Case presentation

Over an eight-month period, a 74-year-old woman developed an enlarging dark lesion (0.7 cm in diameter) on the medial aspect of her left foot (Figure 1).Dermoscopy revealed an asymmetrical lesion with an irregular border. There were several irregular blue–black to dark red globules of various sizes (Figure 2). The globules were separated by irregular pale patches containing numerous dark pigment dots. There was no well-formed pigment network. The excision biopsy showed an epidermis with large nests of deeply pigmented atypical melanocytes. These penetrated into the upper dermis, and there were areas of fibrosis containing melanophages (Figure 3).