In lichen striatus, sections show a lichenoidinfiltrate involving an epidermis which is usually acanthotic (figure 1). The infiltrate can be very dense or quite sparse (figures 1, 2) and there may be numerous melanophages in the superficial dermis. Apoptotic keratinocytes are usually seen at all levels of the epidermis.
The infiltrate typically extends to involve eccrine structures (figure 3).
Lichen planus or lichen planus-like keratosis – The infiltrate does not usually involved eccrine glands and apoptotic keratinocytes are mainly limited to basal epidermis rather than all levels of the epidermis.
Annularlichenoiddermatitis of youth – The histology may be identical and annular lichen striatus may actually be the same disorder.
Unilateral laterothoracic exanthem – May also exhibit eccrine infiltrates
Pathology of the Skin (Fourth edition, 2012). McKee PH, J. Calonje JE, Granter SR