Renal lupus vasculitis is a rare vascular lesion complicated with systemic lupus erythematosus (SLE). We report an unusual case of true renal lupus vasculitis with antineutrophil cytoplasmic antibodies (ANCA)-negative pauci-immune glomerulonephritis in a patient with SLE. A 32-year-old woman presenting with hematuria and overt proteinuria was admitted to the hospital. She had been diagnosed with SLE at 16 years of age and treated with prednisolone, hydroxychloroquine, and methotraxate. A kidney biopsy revealed 42 glomeruli with ischemic wrinkling, and segmental loop necrosis with fibrin deposition. Prominent in-flammatory cell infiltration of interlobular arteries and afferent arterioles with severe necrosis was demonstrated. No electron-dense and immune deposits in the glomeruli were observed by immunofluorescent and electron microscopy; in contrast, those in the renal vascular wall showed a full-house pattern. Antiphospholipid antibodies and ANCA were negative. The patient was treated with monthly intravenous cyclophosphamide pulses and high dose steroid, and showed good response on further follow-up. (J Rheum Dis 2015;22:34-38)

Keywords: True renal lupus vasculitis, Pauci-immune glomerulonephritis, Systemic lupus erythematosus