Abstract
A 52-year-old Japanese man visited our department, complaining of blackish discoloration and edema of lower legs. He had received oral minocycline therapy for more than 3 years prior to the visit. Histopathological examination of lower legs revealed increased melanin granules in the basal layer of the epidermis and extravasation of erythrocytes and the deposit of hemosiderin- like particles in the upper dermis. Electron microscopic studies revealed that electron dense materials were contained in the cytoplasms of dermal macrophages, partially were in the lysosomes. From these results, we diagnosed this case as hyperpigmentation caused by the administration of minocycline. The discolorations gradually improved by discontinuence of minocycline.
