Urinary cytodiagnosis of renal involvement in disseminated histiocytic lymphoma.

Two cases of patients with disseminated histiocytic lymphoma are presented in which positive urine cytology provided evidence of renal involvement. In addition to malignant cells, the urine sediment characteristics included renal tubular epithelial cell exfoliation, renal epithelial fragments and pathologic cast formation, which distinguished renal from lower urinary tract involvement. Such cytologic observations may be useful in differentiating among the various causes of renal disease in patients with malignant lymphomas.