Epithelioid cell granulomas in urine cytology smears: Same cause, different implications.

Tuberculosis of the urinary tract is usually secondary to tuberculosis of the kidney. Multinucleated giant cell histiocytes, often with peripheral nuclei (Langhans' cells), may be identified. Acid-fast bacilli on smear or positive urine cultures confirm the diagnosis. Similar findings can also be seen in patients treated with Bacillus Calmette Guérin (BCG) for transitional cell carcinoma or after bladder surgery. Here, we present two cases showing epithelioid cell granulomas and multinucleated giant cells on urine cytology, and discuss the differentiating features on cytomorphology and their therapeutic implications.