Kidney Biopsy Findings in a Patient With Fever, Bilateral Pulmonary Infiltrates, and Acute Renal Failure

(A) Necrotizing interstitial inflammation (hematoxylin and eosin; original magnification ×100). (B) Fibrinoid necrosis of an arteriole with infarcted glomerulus; these structures are surrounded by interstitial caseating necrosis. (C) The interstitium is diffusely infiltrated by numerous lymphocytes and macrophages and there is focal necrotizing granuloma (hematoxylin and eosin; original magnification ×100). (D) The granuloma shows central caseating necrosis with mostly mononuclear inflammatory cells at the periphery and a large Tuton-type multinucleated giant cell.