Parallel furrow pattern

Dermoscopic Description
Pigment in the furrows of the dermatoglyphs (fingerprints) on the palms and soles

What the structures correspond to histologically
Melanin in the keratinocytes of the furrows.

Lesions in which the structures arise
Benign acral naevi typically have a parallel furrow pattern, but it may also be seen in parts of some acral melanomas.