Histologische und elektronenmikroskopische Befunde bei Histiocytosis gigantocellularis (multizentrischer Retikulohistiozytose)

Abstract

Histological and electron microscopic examination has been carried out on the biopsies from a patient with histiocytosis gigantocellularis. The following findings have been observed. (1) The cells of histiocytosis gigantocellularis have characteristic granules of different size, form, and electron density, mostly showing a lamellar structure, as well as a membranous limit. These granules are probably synthetized within the cells. Their chemical composition and function are unknown. (2) Similarity between the electron-dense granules and those of Merkel’ cells, as well as the richness of unmyelinic nerve fibers in the immediate environment of the granuloma cells are discussed. Desmosomal structures have not been observed, but there are many cytoplasmic processes which are cogged in labyrinth-like fashion, partly forming a membranous complex. (3) The fine structure of the nucleolus, a well-developed endoplasmic reticulum, as well as a large amount of microfibrils and intracellularly localized collagen fibrils are features of fibroblasts, and may possibly be a transition stage of the granuloma cells. It is supposed that granuloma cells represents a degree of differentiation between reticulum cells and fibroblasts on the one hand and histiocytes (macrophages) on the other. Enlarged hollows are interpreted as a phagocytotic phenomenon of storing of lipids. (4) The nature of the stimulus leading to the formation of systematized giant cell granuloma is thus far unknown.