Abstract
A rat model of antineutrophil cytoplasmic antibody (ANCA) associated vasculitides reveals crescentic glomerulonephritis as seen in human renal biopsies and diffuse lung hemorrhage that is not well documented in human lung biopsies. A 64-year-old male, with shortness of breath and mild elevation of serum creatinine, was found to have a positive serum test for ANCA, but negative antiglomerular basement membrane antibody. A renal biopsy showed pauci-immune type of crescentic glomerulonephritis and focal arteritis. The prior lung wedge biopsy was retrospectively reviewed to show diffuse hemorrhage and hemosiderosis with focal giant cells. In addition, small arteries revealed subtle neutrophil aggregation, and margination along vascular endothelium, but no definitive vasculitis. The pathology of ANCA associated vasculitides results from activated neutrophils by ANCA and subsequent activation of the alternative complement cascade with endothelial injury, neutrophil aggregation and margination. Our findings, after the correlation between lung biopsy and renal biopsy, imply that the top differential diagnosis in the lung biopsy should be microscopic polyangiitis when diffuse pulmonary hemorrhage and hemosiderosis are present in this ANCA-positive patient.
Highlights
Introductionantineutrophil cytoplasmic antibody (ANCA) associated systemic vasculitides clinically range from microscopic polyangiitis to granulomatosis with polyangiitis (used to be called Wegner’s granulomatosis) to eosinophilic granulomatosis with polyangiitis (used to be called Churge-Strauss syndrome)
In humans, antineutrophil cytoplasmic antibody (ANCA) associated systemic vasculitides clinically range from microscopic polyangiitis to granulomatosis with polyangiitis to eosinophilic granulomatosis with polyangiitis
The differential diagnosis for diffuse pulmonary hemosiderosis includes idiopathic pulmonary hemosiderosis versus Goodpasture’s syndrome, which is supported by a positive test for antibasement membrane antibody [15, 16]
Summary
ANCA associated systemic vasculitides clinically range from microscopic polyangiitis to granulomatosis with polyangiitis (used to be called Wegner’s granulomatosis) to eosinophilic granulomatosis with polyangiitis (used to be called Churge-Strauss syndrome). In patients with positive ANCA, renal biopsies mainly show crescentic formation in glomeruli as one unique feature of vasculitis (called primary crescentic glomerulonephritis), leading to acute renal failure [4, 10]. The rat model of ANCA associated vasculitides reveals crescentic glomerulonephritis as seen in human renal biopsies and diffuse lung hemorrhage [11] that is not well documented in human lung biopsies. We correlated both the lung biopsy and renal biopsy in a patient with positive ANCA and suggest that microscopic polyarteritis should be in the top differential diagnosis for findings of diffuse hemorrhage and hemosiderosis in the lung under this condition
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