Anti-neutrophil cytoplasmic antibody vasculitis presenting with bilateral renal vein thrombosis

We report a case of anti-neutrophil cytoplasmic antibody (ANCA)-associated necrotizing crescentic glomerulonephritis presenting with bilateral renal vein thrombosis and pulmonary emboli in a patient who also had a lupus anticoagulant and anti-cardiolipin antibodies. Although the link between venous thrombosis and ANCA vasculitis is well established, the coexistence of renal vein thrombosis is unusual. Furthermore, despite the positive ANCA, he was initially negative for antibodies to myeloperoxidase (MPO) and proteinase-3 (PR3), illustrating that a positive ANCA may be significant despite a negative test for antibodies to MPO and PR3.