PYGM and disorder of glycogen metabolism: HE, MGT, and ATPase stains are essential for the diagnosis and differential diagnosis of muscle diseases; PAS, oil red O, NADH-TR, SDH, COX, myophosphorylase, amylopectinase phosphofructokinase, and adenylate deaminase staining were used to exclude glycogen storage diseases, mitochondrial myopathy, lipid storage myopathy, and so on.