muscle biopsy

Indications

• generalized disorder with multiorgan system involvement (muscle is easily accessible tissue)
  • sarcoidosis
  • vasculitis
• primary neuromuscular disease

Contraindications

Caution:

• muscle pathology is frequently multifocal & not diffuse
• biopsy of uninvolved area of muscle may not show pathology

Procedure

• frozen sections necessary
• formalin fixation destroys muscle fiber architecture & inactivates enzymatic activity useful for diagnosis
• electron microscopy for ultrastructure

Interpretation

Features of interest:

• changes in fiber size & shape
• abnormalities in distribution of fiber type
• changes is sarcolemmal nuclei
• degeneration & regeneration of muscle fibers
• inflammatory infiltrates

More general terms

• tissue biopsy