Hietanen, J. Acantholytic cells in pemphigus. A scanning and transmission electron microscopic study.Acta Odontol. Scand. 1982, 40, 257–273Scanning electron microscopy (SEM) was performed on oral scrapings from seven patients with pemphigus vulgaris and one with pemphigus vegetans as well as on skin samples from one of (hose with pemphigus vulgaris. The unstained, fixed, critical-point dried cells were identified with the aid of a light microscope. On the basis of the surface apperance, three main types of acantholytic cells were identified: smooth-surfaced, wrinkled, and microvillous. The acantholytic cells were rounded to ovoid and some showed either a central bulging or a concavity. Small, rounded to ovoid holes or indentations (diameter 0.1–0.3μm) were observed on most cell surfaces. The surfaces of acantholytic cells were occasionally occupied by a few micro-organisms. Neutrophilic polymorphonuclear leuco-cyte/acantholytic cell rosettes were studied by SEM. No gap between acantholytic cell and surrounding leucocytes could be demonstrated. It is postulated that neutrophils may mediate the cytolysis of antibody-coated acantholytic cells. Oral scrapings from one patient with pemphigus vulgaris were collected for transmission electron microscopy (TEM). The acantholytic cells were rounded or ovoid and usually had centrally placed nuclei. Tonofilaments were either randomly distributed or concentrically arranged around the nucleus. In other acantholytic cells there was a halo containing vesicles of varying size around the nucleus. TEM findings suggest that acantholytic cells represent dead or dying cells. Both TEM and SEM findings suggest that when acantholytic cells first separate they may show variable numbers of microvilli, which are probably lost in older acantholytic cells.