Muscle fiber hyaline bodies (HP_0100306) is subsarcolemmal, eosinophilic glass-like regions in the cytoplasm of muscle fibers. Hyaline bodies show significant reactivity to myofibrillar ATPase after acid pre-incubation and with immunohistochemistry, show intense reactivity with only slow myosin heavy chain. Electron microscopy of the affected areas show a lack of myofibrils and a uniform, finely granular matrix, sometimes suggesting a filamentous nature, containing few scattered nuclei and mitochondria. Also known as: Muscle fibre hyaline bodies.