Fibrinoid necrosis of the epithelial cells of the skin.

It has been shown in previous studies that fibrinoid necrosis not only occurs in connective tissue and in vessel walls, but can also be observed in the liver cells under special conditions and can also be provoked experimentally. It was observed in the present study that certain dermatoses (cases of the herpes group, erythema multiforme, drug eruptions, Lyell's toxic epidermal necrolysis, pityriasis lichenoides acuta, and skin affected by UV-rays) were associated with "eosinophilic necrosis" in the epithelial cells which morphologically corresponded to the fibrinoid necrosis of the connective tissue and of the liver cells described previously. Besides toxic, infectious and septic conditions, circulatory disturbances (hypoxia, anoxia) appear to have a special significance. Observations by way of the light and fluorescence microscope revealed the characteristics of keratin variants and precursors in some necrobiotic cells which influence the peculiar properties of fibrinoid necrosis of the skin epithelia. The role of the mixed paraproteins is emphasized and reference is made to the role of a mixed paraprotein ("keratofibrinoid") which is formed in the course of the regressive process and to which the morphological changes may be attributed.