1. CPC #3 Pathology

2. Radical Nephrectomy Three intrarenal masses with cystic change (9, 7, and 5cm) Nodular Mass (3cm) in perirenal fat

5. Not all Renal Tumors (Masses) are Renal Cell Carcinoma! Angiomyolipoma Oncocytoma Xanthogranulomatous Pyelonephritis Malakoplakia Adrenal Rest

6. Xanthogranulomatous Pyelonephritis Subacute/chronic inflammation forming a mass lesion in the kidney Tender unilateral flank mass Nephrolithiasis (70%) –Long term recurrent obstruction Adults Female Predominance (2:1)

7. Xanthogranulomatous Pyelonephritis Gross: –yellow mass often extending into perirenal fat, mimicking renal cell carcinoma Microscopic: –Lipid-laden macrophages –Fibroblastic proliferation –Lymphocytes, plasma cells –Microabscesses Microbiology: –Often Proteus mirabilis, E. Coli

11. CD68

12. Diagnosis Xanthogranulomatous Pyelonephritis

13. ACID-FAST STAIN

15. Diagnosis Xanthogranulomatous Pyelonephritis Numerous Acid-fast Bacilli

16. Similar Cases in Literature Shah HN et al. Renal tuberculosis simulating xanthogranulomatous pyelonephritis with contagious hepatic involvement. Int J Urology 2006;13: 67-68. Izbudak-Oznur et al. Renal tuberculosis mimicking xanthogranulomatous pyelonephritis: ultrasonography, computed tomography and magnetic resonance imaging findings. Turk J Pediatr 2002;44: 168-171

17. Important Point Immunocompromised patients often do not form granulomas well One may see Mycobacterial or Fungal Infections without well-formed granulomas