Occurrence of myofibroblasts in the different phases of morbus Dupuytren (Dupuytren's contracture).

Twenty-one surgically removed specimens of Morbus Dupuytren (M. D.) were studied by light and electron microscopy. The cell type observed in the proliferative phase shows the basic ultrastructural features of fibroblasts, while the majority of the cells in the involutional phase resemble myofibroblasts. Myofibroblasts exhibit ultrastructural characteristics of both smooth muscle cells and fibroblasts and are said to behave functionally like smooth muscle cells. In the residual phase, typical fibrocytes of connective tissue are found. These findings confirm the concept that fibroblasts are capable of converting into myofibroblasts and demonstrate the myofibroblasts represent an intermediate cell type of transitional cellular differentiation. The significance of myofibroblasts for the development of the contracture of M. D. is discussed.