[Ultrastructural findings in Arndt-Gottron's scleromyxedema].

The ultrastructure of a skin biopsy taken from a 64-year-old patient with clinically typical scleromyxedema has been studied. Histologically, the disease is characterized by dermal depositions of acid mucopolysaccharides, as well as an increased number of fibroblasts and tissue mast cells. Electron microscopically, the collagen microfibrils exhibited irregularities of their shapes and widths. In addition, the elastic fibres were unevenly contrasted with small defective areas of the matrix, and there was loss of fibrils. We also encountered a substantial number of highly active "dendritic" fibroblasts that frequently contained phagolysomal cytoplasmic inclusions. Probably these cells are responsible for the increased deposition of newly formed collagen fibres and elastic material. Furthermore, peculiar variants of fibroblasts are described, the cytoplasms of which were replete with heterolysosomal and autolysosomal inclusions. Finally, the tissue mast cells showed unusually large specific granules, so that these cells may also take part in the pathological process.