Ichthyosis hystrix (Curth-Macklin). Light and electron microscopic studies performed before and after etretinate treatment.

Clinical and light and electron microscopic observations of a 16-year-old male patient suffering from ichthyosis hystrix (Curth-Macklin) are presented. The patient had no family history for this disease. The diagnosis was based on the distinct electron microscopic finding of continuous perinuclear tonofibril shells in the keratinocytes. About 10% of the keratinocytes were binucleate and one third contained conspicuous vacuoles. The steroid sulphatase activity in a skin biopsy was normal. Etretinate treatment proved beneficial during the first year of therapy. Later the treatment was less effective. The basic genetic defect persisted in the phenotype of the keratinocytes during etretinate therapy, but the exceedingly thick horny layer was considerably thinned.