Abstract
Background：Extracutaneous vasculitis is a rare manifestation of systemic lupus erythematosus（SLE）. We report a case of SLE with pathological small vessel vasculitis, and review the literature. Case presentation: A 60-year-old woman referred to our hospital with edema of the left leg and positive antinuclear antibodies. Laboratory data revealed lymphocytopenia and hypocomplementemia. Anti-DNA and antiphospholipid antibodies were positive. Contrast-enhanced computed tomography showed deep vein thrombosis in her right leg. We made a diagnosis of SLE and antiphospholipid syndrome. However, there was no evidence of thrombosis in her left leg. Magnetic resonance T2-weighted imaging revealed high-intensity areas in the left soleus muscle. Histological analysis of muscle biopsy showed necrotizing vasculitis. She was treated with prednisolone（0.6mg/kg/day）and hydroxychloroquine, which improved the edema. We made a diagnosis of lupus vasculitis.
Discussion: Vasculitis prevalence in SLE is reported to be between 4 % and 36 %. In cases of lupus vasculitis, cutaneous lesions are most frequent. Skeletal muscle vasculitis is seldom reported in SLE. However, its actual prevalence may be underestimated because it is sometimes asymptomatic and often lacks creatine kinase elevation.
Conclusion: We described a case of SLE with biopsy-proven skeletal muscle vasculitis. Skeletal muscle vasculitis is difficult to diagnose because of its non-specific manifestations. We should not miss slight signs of skeletal muscle vasculitis such as limb edema, and proceed with further investigation if suspected.
