Keratosis lichenoides chronica: lichen planus variant or disease entity? Clinical, immunohistopathological and electron microscopic study

ABSTRACT

The aim of this work was to perform a comparative, clinical, routine, histologic, immunohistochemical and electron microscopic study on 4 cases of keratosis lichenoides chronica [KLC] and 12 cases of lichen planus [LP] to see whether KLC is a variant of LP or is a distinct entity. The clinical findings in the studied KLC cases showed keratotic violaceous papules and psoriasiform plaques. The histopathological findings showed lichenoid and spongiotic pattern of inflammation. The electron microscopic findings showed many degenerating keratinocytes that culminate in the colloid bodies. Also, colloid bodies were seen between collagen bundles. The horny layer was thickened and showed parakeratotic lamella that appeared as corneocytes containing lipid droplets. In conclusion, KLC is most probably a special entity with characteristic clinical and immunohistological features different from LP, although some points of interest are similar between them