Urine cytopathology
Urine cytopathology is a large part of cytopathology.
This article deals only with urine cytopathology. An introduction to cytopathology is in the cytopathology article.
DDx
Common
- Negative for malignancy.
- Urothelial carcinoma.
- AKA urothelial cell carcinoma, abbreviated UCC.
- Urothelial carcinoma with squamous features.
- Polyomavirus infection.
- Acute inflammation.
- Chronic inflammation.
Rare
Usually not reported
- Candida.
- Quite common.
- Large (benign) squamous component.
- Usually contamination from gential tract (in females).
Normal
General
- Benign cells are often in small clumps.
Cell types
Practical cell typing:[1]
Nucleus | Cell border | |
---|---|---|
Urothelium | Larger | Smooth/elliptical |
Squamous epithelium | Smaller | Irregular/jagged |
Degenerative cells
Features:
- Nucleus protrudes through cell membrane.
- Chromatin degeration:
- "Cobweb" appearance - white holes/pale staining.
- White holes/frayed appearance.
- Small clumps of chromatin at the edge of nuclear membrane.
- Frayed cell membrane/irregular cell membrane.
- Vacuolated cytoplasm - "moth-eaten" appearance.
- Normal urothelial cytoplasm is dense and has no vacuoles.
Tabular DDx
Urothelial carcinoma versus benign urothelium
Urothelial carcinoma | Benign urothelium | Use of feature | Utility | |
---|---|---|---|---|
Nuclear hyperchromasia | Present | Absent | r/i & r/o UC | Strong |
Nuclear-to-cytoplasmic (NC) ratio | ~1:1.2 | ~1:2 | r/i & r/o UC; 1:>=2 suggests benign | Strong |
Nuclear membrane irregularity (NMI) | +/- | Absent | r/i UC; presence strong predictor of malignancy (absence of NMI of little value) | Moderate |
Cytoplasm | Green/grey | Green or grey & granular | r/o UC; granular (suggests degeneration) | Moderate |
Coarse chromatin (CC) | Present | +/- | r/o UC; absence of CC suggest benign | Moderate |
Nucleoli | In scattered cells | +/- in reactive | Not useful | Nil for diagnosing UC |
Nuclear size | >2.5X normal | Usu. <=2X normal | Alone not much value, many large cells benign, many small cells malignant | Limited value, NC ratio much better measure |
Degeneration versus UC[2]
Urothelial carcinoma | Degeneration | |
---|---|---|
Architecture | Usually single cells | Often small clusters |
Cell borders | Sharp | Fuzzy/frayed |
Cytoplasm | Green, solid | Grey, lacy/moth eaten |
Nuclear membrane | Irregular | Usually regular |
Chromatin | Granular/coarse | Granular/coarse |
Polyomavirus versus urothelial carcinoma
Urothelial carcinoma | Polyoma virus | |
---|---|---|
Architecture | Often single cells | Single cells |
Nucleus size | Often 3-4X normal urothelial cell | 2X normal urothelial cell nucleus (should not be larger) |
Chromatin | Clumped or "dancing" | Ground glass inclusions/smudged |
Nuclear membrane | Usually irregular | Regular |
Urothelial carcinoma vs adenocarcinoma
The default diagnosis is urothelial carcinoma as this is the most likely if there is no prior history of malignancy.
Urothelial carcinoma | Adenocarcinoma | |
---|---|---|
Vacuoles | None | Present - mucin filled |
Cytoplasm | Dense appearing | Fluffy |
Chromatin | Coarse - clumped or "dancing" | Fine |
History | None | History of adenocarcinoma |
Nucleoli | Often present, multiple | Usually only one - every tumour cell |
Notes:
- Both have eccentric nuclei.
Human polyoma infection
Main article: Polyomavirus nephropathy
General
- Caused by Human polyomavirus, AKA BK virus.[3]
- Associated with immunosuppression/immunodeficiency.
- BK virus related to JC virus.
DDx:
- Urothelial carcinoma.
Cytology
- "Decoy cells":
- Usually 2x the size of a normal urothelial cell nucleus.
- Single cells - important feature.
- Scant "degenerative-appearing" cytoplasm.
- High NC ratio.
- Intranuclear inclusions - key feature.
- Central smudging (or "wash-out") of the chromatin/"Ground glass" chromatin.
- Surrounded by clear halo just deep to the nuclear membrane.
- Nuclear membrane clumping.
Notes:
- Normal urothelial cell nucleus ~ 1.5X the size of a lymphocyte.
Images:
IHC
- JC/BK virus.[6]
"Inflammation" in urine specimens
- One should resist the temptation to call "inflammation" in urine specimens, as processing concentrates the WBCs.
- If the quantity of WBCs is truly "excessive"... then it ought to be called.
Urothelial cell carcinoma
Main article: Urothelial cell carcinoma
- Abbreviated UCC.
General
- Very hard/impossible to diagnose low-grade UCC on cytology.
- The diagnosis of low-grade UCC is based on architecture (papillae).
Cytology
Features:[7]
- "Large nuclei" (3-4X the size of a normal urothelial cell) - low power feature.
- Hyperchromasia - low power feature.
- Irregular nuclear membrane - key feature.
- Increased NC ratio.
- Often uniform - when comparing malignant cells.
- Nuclear size variation, >=2X other malign. looking cells - very useful.
- +/-Large irregular nucleoli - common.
Minimal criteria:
- Criteria #2-4.
Notes:
- Coarse chromatin may be benign.
- Fine/non-granular chromatin suggests benign.
- One does not usually call squamous cell carcinoma on cytology.
- If features of squamous differentiation are present one calls urothelial carcinoma with squamous features.
DDx:
- Degeneration.
- Polyomavirus.
Schistosoma
- Associated with squamous cell carcinoma of the bladder.
Histology
Features of ova:
- Elliptical ~80 micrometres max dimension.
- S. haematobium has a "spike" approx. the size of a PMN.
Image:
See also
References
- ↑ SM. 7 January 2010.
- ↑ Adapted from GS. 2 February 2010.
- ↑ Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 681 (Q26). ISBN 978-1416025887.
- ↑ Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 681-2 (Q26). ISBN 978-1416025887.
- ↑ SB. 27 January 2010.
- ↑ http://www.acta-cytol.com/toc/auto_abstract.php?id=22895
- ↑ Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 682. ISBN 978-1416025887.
- ↑ SM. 12 January 2010.