EFFUSION CYTOLOGY OF RENAL-CELL CARCINOMA

BACKGROUND. Effusions in patients with renal cell carcinoma are rare; the clinicopathologic features of these patients have not been describ ed fully. METHODS. All effusions from patients with renal cell carcino ma obtained between 1986 and 1997 at the study institution were review ed. RESULTS. Twelve effusions from 9 patients were benign, and 8 effus ions from 7 patients were malignant. Patients with sarcomatoid tumors presented early with benign effusions, and patients with papillary tum ors presented later with malignant effusions. Patients with clear cell tumors were intermediate. The majority of patients who developed mali gnant effusions had tumors that were classified as T3 or higher (accor ding to the American Joint Committee on Cancer) at the time of resecti on. Tumor cells had abundant clear to vacuolated cytoplasm, large nucl ei, and prominent nucleoli. Cells from clear cell and papillary tumors could not be distinguished in effusion specimens unless papillae were present. At last follow-up 13 of 15 patients were dead of disease wit hin 2 years of the onset of effusion (median 24 weeks; range, 1-93 wee ks), including 7 of 9 patients with benign effusions. CONCLUSIONS. Mal ignant effusions due to renal cell carcinoma most commonly occur in pa tients with papillary and clear cell tumors. Malignant effusions from these two tumor types are difficult to distinguish unless papillae are present. Effusions associated with renal cell carcinoma confer a poor prognosis. (C) 1998 American Cancer Society.