Bacillus Calmette-Guérin (BCG)-related granuloma
- Multiple granulomas with or without caseation.
- Bacteria (Mycobacterium bovis) may be demonstrable by acid-fast stains.
Post-transurethral resection granuloma (Post surgical necrobiotic granuloma)
- Characterized by central fibrinoid necrosis surrounded by palisaded histiocytes (image A), (image B), (image C), & (image D).
- Morphologically resemble rheumatoid nodule.
- Granulomas may be long or serpinginous.
- Surrounding inflammation of lymphocytes and plasma cells, and eosinophils in early lesions.
- Often caused by Mycobacterium tuberculosis and may follow renal tuberculosis.
- Early lesion often occurs at the ureteral orifice as mixed acute and chronic inflammation with non-caseating granulomas.
- Larger granulomas may have central caseation, which is surrounded by histiocytes and with multinucleated giant cells (Langhans type).
- Acid-fast staining confirms the presence of tuberculosis bacteria.
- May cause obstruction of ureteral outlet.