ABSTRACT
A hypothetical role of mast cells, endothelial cells and fibroblasts, in the pathophysiology of scleroderma has been proposed. The present study aimed at the illustration of the ultrastructural changes of these cells, in particular, in the skin of patients with scleroderma. In the following work, electron microscopic examination demonstrated a spectrum of degranulated mast cells as well as different grades of cell-activation evidenced by presence of hypodense granules with increased cytoplasmic organelles such as rough-surface endoplasmic reticulum [RER], polysome and mitochondria. The fibroblasts showed numerous dilated RER, intra and extracytoplasmic filaments. Some fibroblast - like cells were seen ingesting some mast cell granules. Evidences of endothelial injury were detected in the form of thickening and stratification of basal lamina and swollen endothelial cells