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Case Reports in Pathology
Volume 2014 (2014), Article ID 286030, 5 pages
http://dx.doi.org/10.1155/2014/286030
Case Report

Top Differential Diagnosis Should Be Microscopic Polyangiitis in ANCA-Positive Patient with Diffuse Pulmonary Hemorrhage and Hemosiderosis

Department of Anatomic Pathology, William Beaumont Hospital, 3601 W 13 Mile Road, Royal Oak, MI 48073, USA

Received 28 May 2014; Revised 13 August 2014; Accepted 16 August 2014; Published 30 November 2014

Academic Editor: Katsuyuki Aozasa

Copyright © 2014 Nicholas D. Ward et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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.