Neuromuscular

Capillary Pathology: Muscle

ELS in BIM
Regional microvasculopathies
  Dermatomyopathy syndromes
Diffuse microvasculopathy
  Systemic Sclerosis
    Minimal Myopathy
    Myopathy
  GvHD
Also see
  Capillary pathology
  Pipestem capillaries

Capillary Pathology with Minimal Myopathy

Disease Association: Systemic Sclerosis 1

Clinical associations Pathology: Endomysial Capillaries

H&E stain
Endomysial Capillaries (Arrow)
  Moderately enlarged
Muscle fibers
  Fiber sizes: Moderately varied

H&E stain


Gomori trichrome stain
Endomysial Capillaries
  Moderately enlarged
  Some have thick basal lamina

Gomori trichrome stain

Endomysial Capillaries
  Moderately enlarged

Congo red stain


VvG stain


ATPase pH 4.3 stain
Endomysial Capillaries
  ATPase positive (Arrow)

ATPase pH 4.3 stain


NADH stain
Endomysial Capillaries
  NADH positive

NADH stain


NADH stain


Acid phosphatase stain
Endomysial Capillaries
  Acid -phosphatase: Mild staining
  Neighboring histiocytes (Arrow)

Acid phosphatase stain

Endomysial Capillaries
  PAS stains capillary basal lamina

PAS stain

Endomysial Capillaries: Basal Lamina
  Irregular increase in basal lamina layers around capillaries (Arrows)

Capillary Basal Lamina: Multiple circumferential layers

Systemic Sclerosis: Capillary Pathology + Myopathy


H&E stain


H&E stain
Myopathy
  Muscle Fiber sizes: Varied
  Small, Immature fibers: Scattered
  Internal nuclei: Some muscle fibers
Endomysial Capillary Pathology
  Capillary sizes: Large
  Capillary basal lamina: Thick
  Endothelial cells: Large in enlarged capillaries
  Rare capillaries are surrounded by cells

H&E stain


Gomori trichrome stain
Systemic Sclerosis
  Endomysial capillaries: Large


VvG stain
Myopathy
  Muscle Fiber sizes: Varied
  Small, Immatur fibers: Scattered
Endomysial Capillary Pathology
  Capillary sizes: Large
  Capillary basal lamina: Thick
  Endothelial cells: Large in enlarged capillaries

VvG stain


VvG stain
Endomysial Capillary Pathology
  Capillary sizes: Large
  Capillary basal lamina: Thick
  Endothelial cells: Large in enlarged capillaries

Congo red stain


NADH stain
Endomysial Capillary Pathology
  Capillary sizes: Large
  Capillary basal lamina: Thick
  Endothelial cells: Large; NADH positive


ATPase pH 4.3 stain
Systemic Sclerosis
Endomysial Capillaries: Large (Arrows)

ATPase pH 4.3 stain
Endomysial Capillaries
  Endothelial cells: ATPase positive
  Capillary basal lamina: Often thick around endothelial cells

ATPase pH 4.3 stain

ATPase pH 4.3 stain

Endomysial Capillaries
  Endothelial cells: Acid phosphatase positive

Acid phosphatase stain


UEA I stain
Endomysial Capillaries
  Size: Often large
  Endothelial cells
    Stain for UEAI
    Enlarged inside thick basal lamina
  Basal lamina (Unstained): Thick

MHC I stain
Endomysial Capillaries
  Size: Often large
  Endothelial cells
    Stain for MHC Class I
    Enlarged inside thick basal lamina
  Basal lamina (Unstained): Thick

MHC I stain

Systemic Sclerosis: Capillary pathology

Alkaline phosphatase stain
Capillaries
  Alkaline phosphatase stain: Increased

C5b-9 stain
Capillaries
  C5b-9 staining


UEA I (Ulex) stain
Capillaries
  Reduced numbers: Many muscle fibers have no adjacent capillary

Systemic Sclerosis: Myopathy
  Muscle fibers
    Varied sizes
    MHC1: Patchy upregulation

MHC Class I stain

MHC Class I stain
Systemic Sclerosis: Myopathy
  Muscle fibers
    Varied sizes
    MHC1: Patchy upregulation, especially by fibers with
      Small size
      Location near perimysium
  Capillaries: Reduced numbers in some regions

MHC Class I stain


LC3 stain
Systemic Sclerosis
  Clusters of muscle fibers have multiple, irregular collectons of LC3 aggregates

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References
1. Acta Neuropathol 2021;141:917-927

10/14/2022