Urine cytology in patients with calculi.

The cytological changes in voided urines were analysed in 154 patients with calculi. No abnormality was seen in 52.6%; 40.9% contained smooth-bordered clusters of transitional cells with essentially normal, centrally placed nuclei. These, when found in routine urines, were reliable in predicting calculi in 62.5% of cases. Of the calculus urines, 6.5% showed features suspicious of differentiated transitional carcinoma. Although their morphological features overlapped with those observed in urines from 40 cases of proved differentiated transitional carcinoma, they contained significantly fewer single and clusters of transitional cells with abnormal nuclear morphology. Histological examination of urothelium adjacent to calculi in eight patients showed no evidence of malignancy although one case showed hyperplasia and severe epithelial atypia.