Brown papules and leukoderma in Darier's disease: clinical and histological features.

We report a Japanese case of Darier's disease with brown and white papules or maculae distributed on the neck, trunk and dorsa of hands. Both brown papules and leukoderma showed typical histological features of Darier's disease. Moreover, there were much fewer melanocytes and melanosomes in the epidermis of both lesions. The corneal layer of the brown papules was far thicker than that of the leukoderma. Therefore, the thick corneal layer of the brown papules may prolong the retention of a few melanosomes or a little melanin to induce hyperpigmentation, while the thin corneal layer of leukoderma may not do so, thereby producing hypopigmentation. The difference in clinical and histological courses after involvement of melanocytes was proposed to be the cause of the discrepancy between the previous reports. We conclude that leukoderma was the primary lesion, the postinflammatory depigmented spots, or the atypical or subclinical eruption of Darier's disease.