Normal urine

• Scanty cellularity usually consisting of single cells (especially in voided urine)
• Umbrella cells and squamous cells seen usually dominate the cytological picture, but deeper layer cells are always seen
• In catheter samples of urine and in washings clusters or sheets of urothelial cells appear commonly
• The presence of a few polymorphonuclear neutrophils is a common finding
• Spermatozoa and corpora amylacea may be seen in males

The squamous cells visible in women are usually contaminants from the vagina. Those visible in men can represent metaplastic changes in the bladder trigone.

Cells from the seminal vesicle can be erroneously identified as malignant. They may have large hyperchromatic nuclei and high nuclear/cytoplasmic ratio. The presence of yellowish granules of pigment in the cytoplasm usually allows correct classification.

Urothelial cells can show degenerative non-neoplastic changes: vacuolation of the cytoplasm, nuclear hyperchromasia, red intracytoplasmic inclusions.