Morphologic features of a myopathy on biopsy
What morphologic features of a myopathy may be seen on biopsy?
Morphologic features of a myopathy include muscle fiber necrosis, phagocytosis and regeneration, increased central nuclei, fiber hypertrophy and rounding, variation in fiber size and shape, and increased endomysial connective tissue.
Multiple stains can be used.
• Hematoxylin and eosin—general information about muscle structure/cellular details
• Modified Gomori trichrome—general information about the muscle structures and cellular details; ragged red fibers; rimmed vacuoles
• ATPase—histochemical fiber type
• Nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR)—differentiates type 1 and type 2 fibers, oxidative activity, cores
• Cytochrome oxidase (COX) and succinic dehydrogenase (SDH)—mitochondrial activity
• Congo red—rimmed vacuoles, amyloid deposits
• Other stains can look for glycolytic enzymes or storage materials.
