Fixed drug eruption: ultrastructural study of dyskeratotic cells

Electron microscopic studies have been carried out on three cases of fixed drug eruption, with particular regard to the dyskeratotic cells. The authors have tried to show the sequence of events leading from a normal basal keratinocyte to a dyskeratotic body. Ribosomes were first increased in number; then the tonofibrillar system looked thicker, cytoplasmic organelles degenerated and numerous melanosomes appeared. Many dyskeratotic bodies were later found in epidermal macrophages and in the intercellular space. Several intra-cytoplasmic desmosomes were found in the dyskeratotic cells and their evolution is discussed. The increased number of melanosomes seen in the dyskeratotic bodies could be due to injury to epidermal lysosomal catabolism or it could be due to an apparent increase in melanosome numbers, within cells whose volume has been reduced.