Neuromuscular

Dermatomyositis with TIF1-γ (TRIM33) Antibodies



Muscle Fiber Pathology Distribution: Near or Around Perimysial vessels


ATPase pH 4.3 stain
Perivascular pathology (Arrows point to perimysial vascular bundle)
 Muscle fibers with abnormal internal architecture near Perimysial vessels

Cytochrome Oxidase stain

Cytochrome Oxidase stain
Perivascular pathology: Abnormal muscle fibers near Perimysial vessels with inflammation

ATPase pH 4.3 stain

Congo red stain
Perivascular pathology: Abnormal muscle fibers near Perimysial vessels

VvG stain

Perivascular Pathology
  Abnormal (small) muscle fibers & capillary loss in region neighboring intermediate sized vessels

UEAI stain

Perifascicular Atrophy, Mild


NADH stain

Capillary Pathology


Esterase stain
Endomysial capillaries
  Stain abnormally for esterase

Esterase stain

Esterase stain

Endomysial capillaries
  Mildly large

Gomori trichrome stain stain


Alkaline phosphatase stain
Endomysial capillaries
  Increased numbers stain with alkaline phosphatase

Alkaline phosphatase stain

Endomysial capillaries
  Staining for C5b-9 in regions with muscle fiber pathology

C5b-9 stain


UEA1 stain
Endomysial capillaries
  Reduced regional staining in TIF1-γ DM patient (Above)
  Normal adult: Every muscle fiber has at least one adjacent capillary (Below)

UEA1 stain


UEA1 stain
TIF1-γ DM patient
  Reduced numbers of stained endomysial capillaries in region near perimysial vessel

UEA1 stain


UEA1 stain
Normal adult: Every muscle fiber has at least one adjacent capillary

Muscle Fiber Pathology: Vacuoles & Aggregates


H&E stain
Cytoplasmic Agregates & Vacuoles

H&E stain

VvG stain

Congo red stain
Cytoplasmic Agregates & Vacuoles

Congo red stain

ATPase pH 9.4 stain
Internal architecture: Irregular
  More abnormal in type 1 muscle fibers

NADH stain

NADH stain


AMPDA trichrome stain
Cytoplasmic Agregates & Vacuoles
  One muscle fiber has cytoplassmic bodies (Below)

Gomori trichrome stain

SDH stain

SDH stain
Mitochondrial pathology
  SDH: Irregular internal architecture; Normal levels of staining
  COX: Irregular internal architecture; Variably reduced levels of staining

COX stain

Acid Phosphatase stain


LC3 stain
LC3: Present in some muscle fiber aggregates
  Similar patterns may occur in DM-VP

LC3 stain

MHC Class I: Upregulation by all muscle fibers

MHC Class I stain

Perimysial Pathology


H&E stain
Vascular Perimysium: Cellularity

H&E stain

H&E stain

CD45 stain
Vascular Perimysium: Cellularity

CD8 stain

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5/8/2019