CPC #3 Pathology

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

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

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)

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

CD68

Diagnosis Xanthogranulomatous Pyelonephritis

ACID-FAST STAIN

Diagnosis Xanthogranulomatous Pyelonephritis Numerous Acid-fast Bacilli

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

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