Light and electron microscopic studies of congenital muscular dystrophy.

Light and electron microscopic examinations performed on muscle specimens from 27 cases of clinically typical Fukuyama type congenital muscular dystrophy (FCMD) revealed the following observations, which had not been documented previously. Histological and histochemical studies demonstrated that opaque fibers were present frequently in all cases. Very small foci of round cell infiltration were demonstrated in 2 out of 27 cases. Electron microscopic study revealed tubular structures which were identical with the ones observed in systemic lupus erythematosus and polymyositis in 6 of 27 cases. They were found in the cytoplasm of the endothelial cells of the blood vessels and the histiocytes in the stroma. It is widely believed that FCMD is a hereditary disorder of autosomal recessive type. However the observations mentioned above, particularly the presence of tubular structures in a significant number of the cases suggest the possibility that external factors such as infection of other inflammatory processes in utero may play an important role in the pathogenesis of some of the CMD cases.