Neuromuscular

Inflammatory Myopathies with Vacuoles, Aggregates & Mitochondrial Pathology (IM-VAMP)

Myositis with mitochondrial pathology (PM-Mito) subtype

Endomysial inflammation
Focal invasion of muscle fibers
Myopathic changes
Mitochondrial disorders
Other

Variant syndrome
  IBM

PM-Mito: Muscle pathology

INFLAMMATION: Predominantly Endomysial


H&E stain

Focal invasion of muscle fibers by immune cells

H&E stain

MYOPATHY

  Muscle fiber sizes: Varied; Largewts fibers hypertrophied
  Connective tissue, endomysial: Increased, mild to moderate



IM-VAMP: MITOCHONDRIAL CHANGES

Cytochrome oxidase (COX) negative muscle fibers


Cytochrome oxidase stain

Succinate Dehydrogenase (SDH) positive muscle fibers


SDH stain

OTHER FEATURES

Perivascular Inflammation: Ocasional

MHC-I Upregulation on muscle fiber surface


LC-3 aggregates in muscle fibers


Return to Inflammatory myopathies
Return to Polymyositis with mitochondrial disorders

8/12/2019