[Ultrastructural similarities between the planus-like reaction of the graft versus host disease and the idiopathic lichen planus (author's transl)].

An ultrastructural study was performed on skin biopsies of eight patients with lichenoid eruption of chronic graft-versus-host disease (GVHD). The lichenoid eruption is similar to idiopathic lichen planus with the injury of the basal cells, the distribution of the numerous colloid bodies, and the presence of regenerative cells. Lymphocytes satellites of injured keratinocytes were observed in those lichenoid eruptions, as well as in the acute phase of GVHD. The numerous mast cells in the lichenoid eruption of GVHD may be related to the connective tissue changes of the patients progressing to a late sclerotic phase of chronic GVHD.