Lichen nitidus: electron microscopic and immunofluorescence studies.

Skin biopsies from a patient suffering from lichen nitidus were studied by electron microscopy and immunofluorescence studies. Complete disintegration of the stratum basale in the central area of the lesion and signs of acantholysis in the border area were found. In the central part of the lesion the dermo-epidermal junction was severely damaged in most places. In the dermal infiltrate, macrophages and lymphocytes were found with a considerable representation of Sézary cells, not previously reported in lichen nitidus. The ultrastructural changes are identical with those found in lichen planus. No in vivo bound immunoglobulins, fibrinogen, or complement C3 were found.