Table 3

Pathology in disorders with inflammation in muscle: comparative patterns

Focal inflammation Perimysial connective tissue fragmentation Myopathic changes Capillary pathology Alkaline phosphatase stain COX− muscle fibres
Myositis + anti-Jo-1 antibodiesPerimysial  connective tissuePresentPerifascicularNonePerimysial connective tissueInfrequent
DermatomyositisPerivascularUncommonPerifascicularYes
Number ↓
Small vesselPerifascicular
PolymyositisEndomysial PerivascularUncommonDiffuse ± focal invasion  of muscle fibresNone± Perimysial connective  tissueNone, or scattered  endomysial
Inclusion body myositisEndomysial PerivascularNoneDiffuse: focal invasion  of fibresNone± Small vesselScattered  endomysial
FasciitisPerimysial  connective tissuePresentNoneNoneNoneNone