4A41.10

Juvenile polymyositis

Polimiosite juvenil

Category

Definition

Juvenile polymyositis is a rare childhood idiopathic inflammatory myopathy. It is frequently misdiagnosed, as it lacks a unique clinical phenotype. Traditionally, it presents with weakness of the proximal muscles that evolves over weeks to months. The primary histologic features are fibre size variability, scattered necrotic and regenerating fibres, and perivascular and endomysial cellular infiltrates.

Exclusions

  • Systemic sclerosis
  • Overlap or undifferentiated nonorgan specific systemic autoimmune disease
  • Antiphospholipid syndrome
  • Vasculitis
  • Lupus erythematosus

Index Terms

Juvenile polymyositisJuvenile polymyositis, necrotisingJuvenile polymyositis, paraneoplasticJuvenile polymyositis with anti-synthetase auto-antibodyJuvenile polymyositis with interstitial lung diseaseJuvenile polymyositis with overlap to non-organ specific systemic autoimmune disorderJuvenile polymyositis with PM-Scl auto-antibody