Primary urinary cytodiagnosis of a bladder small-cell carcinoma.

A small-cell undifferentiated tumor of the bladder in a 69-yr-old man with asymptomatic hematuria is described. Urine cytology showed abundant, small, round-to-oval hyperchromatic cells with coarse chromatin, nuclear molding, and high nuclear/cytoplasmic ratios. A primary cytodiagnosis of small-cell undifferentiated cancer with associated severe urothelial atypia was made. Immunohistochemical stains were negative for neuron-specific enolase, leukocyte common antigen, chromogranin, epithelial membrane antigen, prostatic acid phosphatase, and prostate-specific phosphatase. The diagnosis was confirmed histologically by studies performed on cystoscopic bladder biopsy material.