IN 1962, Engel1 first described a "cytoplasmic body" in pathologic human skeletal muscle fibers and in chick embryo skeletal muscle fibers in vitro. Since then, several reports2-5 dealing with the ultrastructure of human skeletal muscle have referred to the cytoplasmic body, but without detailed description.
Recently, we examined a patient suffering from late-onset atrophy, with weakness of the hands, peroneal muscles, and shoulder girdle. Skeletal muscle fibers contained numerous inclusions resembling the cytoplasmic body. This article describes the ultrastructure of various types of inclusions and the possible origin of these inclusions.
Report of a Case
In January 1966, a 53-year-old man noted a "heavy feeling" in his legs after slight exertion, which gradually increased. After six months he had difficulty walking and holding his arms overhead. At age 54, in May 1967, he was admitted to Nagoya National Hospital. His health otherwise had been good except for