This is useful in two situations: bullous dermatoses with suspected autoimmune pemphigus and vesicular dermatoses presumed to be of viral origin. Cytodiagnosis does not replace biopsy, but can provide important information in a very short time. The technique is simple:–excising the roof of a recent vesicle or blister with a scalpel or scissors;–after removing the contents, scrape the base with the blade of the scalpel or with a curette;–spread a thin smear on a microscope slide and air dry;–stain the smear using May-Grünwald-Giemsa staining. The stained smear is examined under a high-magnification light microscope. The cytopathogenic effect of herpes viruses (HSV, VZV) is characterized by large uni- or multinucleated keratinocytes with a frosted glass nucleus and sometimes a large intranuclear inclusion. In bullous dermatoses (see chapters 10-11), the smear consists primarily of inflammatory cells: neutrophils, eosinophils, lymphocytes, and Langerhans cells. Numerous eosinophils suggest pemphigoid. To confirm pemphigus, look for acantholytic keratinocytes: rounded cells with large nuclei and basophilic cytoplasm condensed at the periphery.
Made with Bullet