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

Figure 1

ANCA associated vasculitides in a 64-year-old man. In the wedge lung biopsy, there was diffuse alveolar hemorrhage (a). The hemosiderosis (hemosiderin-laden macrophages) was confirmed by positive iron staining in (b) (magnification ×100 for both (a) and (b)). High power view in the lung showed focal giant cell (c) and neutrophil aggregate and margination along the endothelium of an artery (d). Renal biopsy revealed cellular crescent formation (e) and focal fibrinoid arteritis (f). Magnification ×400 in (c)–(f).

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