Neuromuscular

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MUSCLE BIOPSY

Methods
  Selection of muscle to biopsy
  Biopsy freezing
  Biopsy procedures
  Biochemistry
    Glycogen pathways
    Mitochondria
  Stains
    Histochemical
    Immune
    Inherited myopathies
  Biopsy request form: PDF

Clinical
  How to read a muscle biopsy
  Indications
  Results: Differential diagnosis
  Pathology: Index
  Unknowns

Nerve biopsy

Vesalius

Gowers

GENERAL INDICATIONS FOR MUSCLE BIOPSIES

SELECTION OF MUSCLE TO BIOPSY

BIOPSY PROCEDURES


HOW TO READ A MUSCLE BIOPSY

General questions to keep in mind
NORMAL MUSCLE
Mean fiber diameter
Age
(Years)
Diameter
(μM)
Birth 12 to 15
1 18
3 20
6 27
8 35
10 40
12 45
15 50
Adult 35 to 85

MUSCLE BIOPSY STAINS & PROCEDURES

Category Method Utility

Perimysial Vessels: Normal


VvG stain
Morphology Hematoxylin & Eosin Muscle fiber pathology; Nuclei
Verhoeff van Gieson (VvG) Connective tissue; Vessel structure;
Intramuscular nerve (Myelinated axons)
Gomori trichrome Connective tissue; Nemaline rods
Cytoplasmic bodies
Fiber Type
  Enzymes

(See MYH)
Myofibrillar ATPase Muscle fiber type grouping or Atrophy
  ATPase pH 9.4 Myosin loss; Type 1 or 2 fiber atrophy
  ATPase pH 4.6Type 2B muscle fibers
  ATPase pH 4.3Type 2C (Immature) muscle fibers
Blood vessels
Oxidative
  Enzymes
NADH-TR Muscle fiber internal architecture;
Tubular aggregates; Cores
Succinate dehydrogenase (SDH) Mitochondrial pathology
  Nuclear DNA encoded complex
Cytochrome oxidase (COX) Mitochondrial pathology
  Mitochondrial & Nuclear DNA encoded
Glycolytic
  Enzymes
Phosphorylase Phosphorylase deficiency
Phosphofructokinase (PFK) PFK deficiency
Hydrolytic
  Enzymes
Acid phosphatase Histiocytes; Lysosomes; Lipofuscin
Esterase, Non-specific Histiocytes (Cytoplasm); Lysosomes;
Neuromuscular & Myotendinous junctions
Denervated (small angular) muscle fibers
Acetylcholinesterase Neuromuscular & Myotendinous junctions
Alkaline phosphatase Regenerating or Immature muscle fibers
Immune disease:
  Connective tissueCapillaries
Muscle fiber necrosis
Storage
  material
PAS Glycogen & Carbohydrate disorders
Alcian blue Mucopolysaccharide
Sudan black BLipid storage
Oil red O Lipid storage
Menadione-αGP Reducing bodies; Dense bodies
Other Congo red Amyloid; Inflammation; Vacuoles
Myoadenylate deaminase
  (AMPDA)
AMPDA deficiency
Cytoplasmic aggregates
Methyl green pyronine RNA
Acridine orangeRNA
Von Kossa Calcium
Alizarin red Calcium
Fixed muscle Toluidine blue Muscle fibers; Capillaries

Mitochondrial Oxidative Enzyme Activities: Methods

MUSCLE BIOPSY RESULTS: Differential diagnosis

Muscle fiber
  Damage
  Internal architecture
  Mitochondrial
  Necrosis
  Nuclei
  Size changes
    With age
    Atrophy
    Hypertrophy
  Storage
  Type disorders
  Vacuoles
Amyloid
Capillary pathology
Complement
Endomysial fibrosis
Inflammation
  MHC-I
Inherited myopathies
  Cytoplasmic proteins
  Extracellular proteins
  Nuclear proteins
  Sarcolemmal proteins
Nuclear pathology

Focal invasion of muscle fiber


Muscle Fiber Pathology

Other Muscle Features

Molecular Pathology: Immunohistochemistry for Inherited Myopathies 1

Cytoplasmic proteins
Extracellular proteins
Nuclear proteins
Sarcolemmal proteins
See: Pathology index
Return to Neuromuscular Home Page
Return to Neuromuscular Evaluations

References
1. J Neuropath Exp Neurol 2005;64:181-193
2. Neuromuscul Disord 2008;18:934-941
3. Molecular Aspects of Medicine 2015; Online Aug
4. J Surg Res 2019;243:27-32
5. J Neuroinflammation 2022;19:97

9/26/2023