Individual Keratinocyte Necrosis in the Epidermis Includes Apoptosis in the Skin: A Case Report.

The patient was a 44-year-old woman with suspected Stevens-Johnson syndrome due to Baktar® (sulfamethoxazole trimethoprim) medication received at our outpatient dermatology clinic. Histopathological examination of the epidermis, dermis, and subcutaneous adipose tissue samples showed numerous necrotic keratinocytes in the epidermis. Apoptotic nuclei were visualized as diaminobenzidine brown deposits with immunoperoxidase staining for cleaved caspase-3. Cleaved-caspase3-positive findings were consistent with eosinophilic material that appeared to be necrotic cells within the epidermis. Therefore, these eosinophilic materials must be apoptotic bodies. Generally speaking, and especially in Japan, these materials are considered necrotic keratinocytes. To our best knowledge, no studies have used apoptotic immunohistochemical markers to examine whether these structures are apoptotic.