The contemporary role of electron microscopy in neuromuscular pathology

Electron microscopy has a strategic position in the diagnosis of neuromuscular disorders. In muscular fibers the main abnormalities includes vacuoles, vesicles, inclusion bodies, sarcoplasmic reticulum modifications and mitochondrial alterations. The differential diagnosis includes polymyositis, inclusion body myositis, some sarcolemmal and nonsarcolemmal dystrophies, lysosomal storage diseases. Degenerative alterations of mitochondria, causing swelling and cristae fragmentation, may be considered also as a precocious feature of drug-induced muscle damage guiding molecular genetic analysis. The ultrastructural approach seems to improve the diagnostic accuracy in muscle disorders, making possible the identification of changes and structures related to new hypothesized pathogenetic mechanisms.