Rheumatoid granuloma of kidney

A seventy-year-old black man with long-standing rheumatoid arthritis who had been treated with corticoids presented with painless hematuria originating from the kidney. The clinical findings were suggestive of a renal cell carcinoma. The resected kidney was markedly enlarged, scarred, and disclosed a necrotic rheumatoid granuloma surrounded by chronic inflammatory reaction. The mechanism of hematuria and the clinical significance of the rheumatoid granulomatous involvement of the kidney are discussed.