A dark reticulated lesion

Case presentation

A 63-year-old man suddenly noted a dark 4 mm diameter lesion on the crown of his balding scalp (Figure 1). Dermoscopy showed a reticulated black network interspersed with small dark dots (Figure 2). Skin biopsy showed an epidermis with an elongated rete ridge system that had darkly pigmented tips (Figure 3). There was no increase in the melanocyte numbers in the epidermis or evidence of junctional nests.