Disorders of transepidermal elimination. Part 1.

Transepidermal elimination (TE) is a mechanism whereby foreign or altered constituents can be removed from the dermis. This process involves unique morphologic alterations of the epidermis, which forms a channel and thereby facilitates extrusion of the desired dermal components. The phenomenon of TE may occur as a primary process characterizing disorders, such as elastosis perforans serpiginosa and reactive perforating collagenosis. Occasionally, TE may occur as a secondary phenomenon. Well-known examples are perforating granuloma annulare and pseudoxanthoma elasticum.