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.