Streaks are linear pigmented projections seen at the periphery of lesions.
Both pseudopods (streaks with bulbous projections at their tips) and radial streaming (streaks without bulbous projections at their tips) are considered to be streaks. Streaks in melanoma are usually observed only focally and asymmetrically at the lesion’s periphery and reflect the radial growth phase of the tumor. On the other hand, streaks that are distributed symmetrically around the entire perimeter of the lesion are seen mostly in pigmented spindle cell nevi (Spitz or Reed). Histologically, streaks represent confluent junctional nests of melanocytes.