Neuromuscular

MYOFIBRILLAR (DESMIN) MYOPATHY

Aggregates
Desmin
  Myopathy
    5th decade
    3rd decade
  Myopathy + AVSF
ZASP

Cytoplasmic aggregates
  Eosinophilic
  Homogeneous


 

H & E stain

H & E stain


Gomori trichrome stain
Cytoplasmic aggregates
  Dark stained regions
  Irregular shapes
  May be several in each fiber

Gomori trichrome stain

Sarcoplasmic membranes
  Absent from regions with desmin-containing cytoplasmic bodies.
  Irregular (moth-eaten) internal architecture is present in several muscle fibers

NADH stain

Myofibrillar apparatus
  Absent from regions with desmin-containing cytoplasmic bodies
  Aggregates are in both fiber types

ATPase, pH 9.4

Desmin aggregates
  Cytoplasmic accumulations
  Various shapes & sizes
  Other desmin staining
    Diffuse in regenerating fibers

 


Anti-desmin antibody

Myofibrillar Myopathy: Desmin mutations


I402N Desmin mutation: 46 year old patient

H&E stain
Fiber size: Varied, Large & Small
Necrosis: Few fibers
Internal nuclei
Endomysial connective tissue: Mildly increased

H&E stain


Gomori trichrome stain
Internal nuclei
Internal architecture: Aggregates; Irregular

HADH stain


Congo red stain
Nuclei: Internal; Clustered; Irregular shapes; Large
Cytoplasm: Congophilic aggregates

Congo red stain


Desmin stain
Desmin: Cytoplasmic aggregates

Desmin stain

I402N Desmin mutation: 24 year old patient

H&E stain
Fiber size: Varied
Endomysial connective tissue: Mildly increased

H&E stain


Gomori trichrome stain
Fiber size: Varied
Endomysial connective tissue: Mildly increased
Internal nuclei
Aggregates: Irregular; Dark stained

Gomori trichrome stain


Congo red stain
Fiber size: Varied
Internal nuclei

Congo red stain


NADH stain
Internal architecture: Mildly irregular


Desmin stain
Desmin: Small or Irregular aggregates

Desmin stain

Desmin Myopathies with Autophagic Vacuoles

R454W Desmin tail domain mutation

H&E stain
Myopathy
  Multifocal pathology
  Muscle fibers
    Atrophy & Hypertrophy
    Clear, irregular vacuoles
  Endomysial connective tissue: Increased

H&E stain

H&E stain

H&E stain


Gomori trichrome stain
Vacuoles
  Irregular shapes
  Contain red-staining material
  Subsarcolemmal or Central
      Invaginations
  Branched
  Extend deeply into muscle fibers
  May contain capillaries

Gomori trichrome stain

Gomori trichrome stain

Cytoplasmic bodies

Gomori trichrome stain

Myopathy
  Muscle fibers
    Varied size
    Internal architecture
      Irregular
      Aggregates
      Vacuoles
  Endomysium
    Connective tissue
      Increased

VvG stain

Internal architecture: Irregular

NADH stain


Congo red stain
Vacuoles: Contain basophilic granular debris
Splits & Invaginations: Extensive; Branched
Nuclei: Large; Irregular shapes; Some have clear centers

Congo red stain


ATPase pH 9.4 stain
Aggregates (Pale areas): In Type I & II fibers

ATPase pH 9.4 stain

Type IIC fibers: Common

ATPase pH 4.3 stain


Caveolin-3 stain
Invaginations & Vacuoles: Lined with Caveolin-3 on membrane

Caveolin-3 stain


Dystrophin stain
Invaginations & Vacuoles: Lined with Dystrophin on membrane

Dystrophin stain

Aggregates: Stain for desmin

Desmin stain

Sural nerve: Mildly reduced number of myelinated axons

Toluidine blue stain

Return to Myofibrillar/Desmin myopathies
Return to Muscle biopsies

3/7/2016