Cytoplasmic inclusion bodies in superior rectus muscle of the eye.

Cytoplasmic inclusion bodies are found in fibers of superior rectus muscle of the eye. They occur in middle-aged and old individuals dying with various unrelated diseases not affecting muscle and in patients with myotonic dystrophy. With light microscopy they can be observed in fibers with pathologic changes, and with electron microscopy they appear to be associated with crystals of probable viral origin. It is suggested that cytoplasmic inclusion bodies in superior rectus muscle are the result of viral activity and may represent an incidental viral infection of the senescent period.