Cytologic features of clear cell carcinoma of the urethra and urinary bladder.

Clear cell carcinoma (CCL) arising in the lower urinary tract is unusual and we report the cytohistologic findings of three cases retrieved from our files. All patients presented with bleeding, and the tumors were localized in either the urethra or bladder base. Filter and cytocentrifuge preparations of the urine were studied and all cases displayed numerous scattered aggregates or single tumor cells in an inflammatory background. The enlarged cells had abundant clear, wispy cytoplasm with discrete vacuolation. Hobnail and signet ring cells were apparent. The nuclei had granular to vesicular chromatin with prominent often multiple nucleoli. The tumors were histologically distinctive and typically had a tubulocystic configuration with varying proportions of papillary and diffuse patterns. One patient has died of metastatic cancer and two are presently free of tumor. The cytohistologic features of this cancer are characteristic and from our review we conclude that this lesion can be diagnosed by cytologic means.