Subtle clues to the diagnosis of the herpesvirus by light microscopy: Herpetic syringitis

Among the numerous infections to which AIDS patients are susceptible, those caused by herpesvirus (simplex and varicella/zoster) are among the most common. Because herpetic infections may be the first manifestations of AIDS and often are associated with poor prognosis, rapid and accurate diagnosis of them is imperative. Herpesvirus infection may be diagnosed histopathologically by the presence of ballooned, acantholytic, and multinucleated keratinocytes; intranuclear eosinophilic viral inclusions; steel gray color of affected keratinocytic cytoplasm and nuclei, chromatin margination, and necrotic acantholytic keratinocytes in older lesions. These changes are often limited to the epidermis, but there may frequently be involvement of epithelia of follicles (herpetic folliculitis) and sebaceous glands as well. Similar changes, although seldom noted, may be present in eccrine ducts and glands (herpetic syringitis). Recognition of subtle histologic clues concerning the secretory and ductal components of sweat glands in an unusual case of herpes infection facilitated rapid diagnosis in an AIDS patient, allowing appropriate treatment.