Abstract
A3-year-old boy was admitted to our hospital because of a prolonged fever，red lips，cervical
lymphadenopathy，a generalized rash，edema of the extremities and ambulation difficulty． A physical examination
demonstrated a facial erythematous rash with edema but no heliotrope rash or Gottron's papules． His ESR and
muscle enzymes such as CK were elevated but CRP was normal． Echocardiography revealed a normal ejection
fraction and no coronary artery dilatation． Clinical findings were thought to be consistent with the diagnosis of
Kawasaki disease（KD）． He was given 2g/kg of intravenous immunoglobulin along with aspirin． Although he became afebrile， his symmetric proximal muscle weakness persisted． An MRI showed hyperintensity of his thigh muscle on T2-weighted images， consistent with myopathy． His muscle biopsy specimens demonstrated perifascisular atrophy, necrosis and variation in fiber size． Given the results of clinica1-pathological findings，in addition to the imaging pictures． the diagnosis was deterlnined to be consistent with juvenile dermatomyositis （JDM）． He was treated with pulse steroids of 3 courses． All clinical and laboratory abnorlnalities were reversed．
We dcscribed， to the best of our knowledge． the first reported case of JDM with features of KD． Clinically it is difficult to differentiate between these two vascuIitis diseases，especially when KD is in its atypical form．
