THE NATURE AND PATHOGENESIS OF DYSKERATOSIS IN HAILEY‐HAILEY'S DISEASE AND DARIER'S DISEASE

The following results were obtained after electron microscopic observation of skin lesions and outgrown epidermal cells (OEC) released from explant cultures in Hailey‐Hailey's disease (HHD) and Darier's disease (DD). It was not always evident that the dissociation between keratinocytes in HHD and DD was caused by separation at the center of the desmosome; it seemed rather to be a phenomenon due to melting apart of cytoplasmic processes. Marked development and deformation of microvilli observed in keratinocytes in lesions of both diseases as well as their disappearance were considered to be phenomena reflecting the degree of cell membrane disturbance accompanying the above disjunction. In particular cases where dissociation progressed remarkably, keratinocytes became round and were released into lacunae (bullae) developed in the epidermis. Some of the keratinocytes had organelles and tonofilaments around nuclei with a circular electron transparent zone between the nuclei and cell membrane; they were presumed to correspond to “corps ronds” observed by optical microscope. Electron microscopically, these specific round cells looked finding as if, in most cases, they had been entirely phagocytized by other keratinocytes. This finding was especially marked in DD, and was designated the “corps ronds phenomenon”. Pathological changes identical with the above were observed in OEC released from explant cultures not only in DD but also in HHD. The “corps ronds phenomenon” was confirmed to occur in vitro. The nature and pathogenesis of acantholysis and dyskeratosis in DD and HHD were inferred from these findings.