Objective To describe the clinical and muscle pathological characters ofdermatomyositis patients with perifascicular atrophy.Method Medical records and muscle biopsy specimens were retrospectively analyzed in 104 cases of dermatomyositis with perifascicular atrophy (PFA) in muscle specimens.Results In clinic, 63% patients combined with interstitial lung disease, 70% with antinuclear antibody positive in serum, 6% with anti-jo-1 antibody positive in serum.According to morphologic changes of muscle biopsy, all specimens were divided into two groups: PFA group and PFA plus focal damage group.Mononuclear cells in muscle were less in PFA group than in PFA plus group.Perivascular inflammatory changes were found frequently in PFA plus group.There was no prominent difference in membrane attack complement (MAC) deposition in intramuscluar capillaries between tow groups, but more obviously in severe cases.Conclusion Patients of dermatomyositis with PFA changes usually combined with interstitial lung disease and antinuclear antibody in serum.Mononuclear cells in muscle were more common in PFA plus focal damage group, especially perivascular infiltration.That suggested inflammatory microvascular changes may play an important role in the muscle fiber damage and meanwhile other organs may be involved.