Microscopic polyangiitis sparing the kidneys in a long-term survivor after allogeneic bone marrow transplantation and graft-versus-host disease.

We report an unusual case of microscopic polyangiitis sparing the kidneys in a long-term survivor of allogeneic bone marrow transplantation. Clinical and pathologic studies revealed cutaneous leukocytoclastic vasculitis and isolated pulmonary capillaritis. Serological studies revealed "double positive": perinuclear antineutrophil cytoplasmic (P-ANCA) antibody testing with anti-myeloperoxidase (MPO) activity and anti-glomerular basement membrane (anti-GBM) antibody. The vasculitis has been successfully controlled with prednisone and cyclophosphamide.