Pigment network

Dermoscopic Description
Intersecting brown lines forming a grid-like reticular pattern. The network can be angulated or rounded.

What the structures correspond to histologically
Increased pigmentation (melanin within the keratinocytes due to melanocyte activation, or within the melanocytes due to melanocyte proliferation) along elongated rete ridges. The "holes" of the network correspond to the suprapapillary plates.

Lesions in which the structures arise
Pigmented networks can be described as typical or atypical. Benign networks are only found on areas where the dermo-epidermal junction is eggbox-shaped, e.g. the trunk and limbs. Dermatofibromas often have a peripheral rounded pigment network. This is due to melanocyte activation along the dermoepidermal junction. This melanocyte activation can also be seen in solar lentigos.