Chapter 8 Answers to discussion questions

Cytology of urine

8.1 Evaluate and compare different preparation methods used in urine cytology.

Consider advantages and disadvantages. Include ease of preparation, cellularity of sample and ease of screening, reproducibility, and cost.


8.2 Urine cytology is of no value in diagnosis of low-grade urothelial carcinoma. Discuss this statement.

Think about histology of low-grade urothelial carcinoma. What does it look like? Describe the cytology of low-grade urothelial carcinoma. Talk about the benign changes that can occasionally look like low-grade urothelial carcinoma.


8.3 Evaluate possible causes of false positive diagnoses in urinary tract cytology.

There is a lot to cover here, include polyomavirus, change due to calculi, treatment effects, sample type (i.e. normal upper tract washings and brushings), and non-specific reactive changes.


8.4 You receive an e-mail from the urologist asking you to review the three previous urine cytology samples for an elderly male patient all of which were reported as ‘Occasional poorly preserved atypical cells with high nuclear to cytoplasmic ratio and irregular nuclear outlines, suspicious but not diagnostic of transitional cell carcinoma’. The urologist states that two cystoscopies have been negative as has a recent CT-urogram.

Worth finding out about full clinical history. Is patient on any systemic medication? Could there be iatrogenic basis; there are many drugs such as cyclophosphamide, used to treat some autoimmune disorders or certain haematological malignancies that produce atypical changes in the urothelium. If this is not the case you need to consider that  this could be a false positive due to degenerative changes, polyoma virus or other reactive changes, but also a true positive diagnosis arising, in the bladder or more likely  in the upper urinary tract, that cannot be seen by cystoscopy..  The question is asking you to “discuss” and this is what is required. Both scenarios are valid, and the discussion needs to be balanced. Also suggest discussing the case with a colleague to obtain second opinion.


8.5 Discuss iatrogenic changes in urinary tract cytology.

Latrogenic changes are common cause for false positive diagnosis in in the urinary tract. The most common are intravesical chemotherapy or immunotherapy. This treatment mobility produces morphological changes in the urothelium than can be mistaken for carcinoma. These include Mitomycin C used for transurethral resection of the bladder to reduce recurrences, and BCG immunotherapy to treat high risk non-invasive carcinoma in situ. Systemic drugs such as cyclosphophamide to treat certain lymphoma and the anaesthesia ketamine may produce atypical changes. 

Back to top