Epidermal changes in lichen planus.

Ultrastructural investigations in 15 patients with lichen planus (LP) revealed a multitude of epidermal changes. The most consistent findings were (1) multiplication, irregular folding or dislocation of the basal lamina, (2) fragmentation with degenerative changes of basal keratinocytes, (3) formation of numerous fibrillar Civatte bodies and, (4) presence of dyskeratotic elements. In addition, mitotic figures of keratinocytes and Langerhans cells were observed. These findings support the view that the primary event in LP represents an injury involving epidermal basal cells. Furthermore, the replacement of destroyed tissue seems to originate not only from the margin of the lesions or the skin appendages but also from unaffected cells within the LP papule.