Pap stain, high power
Singly scattered and focally clustered high grade urothelial carcinoma cells.
In this example, the cells may be mistaken for degenerated cells and may be overlooked.
Histiocytes or degenerating urothelial cells do not have nuclear membrane irregularities and chromatin pattern that of high grade carcinoma
Pap stain, low power
Nuclear hyperchromasia catches the eye at low power and nuclear irregularity can be identified.
Note the background necrosis, which is neither diagnostic nor required.
Pap stain, medium power
Numerous distorted cells of high grade carcinoma. Note that despite distortion, the irregular nuclear outlines and coarse chromatin can be identified and aid in the diagnosis.
Note the envelope shaped oxalate crystals in the background
Pap stain, high power
Usually the high grade urothelial carcinoma cells are present singly. In this example the cells are in a small cluster and show marked nuclear atypia
Pap stain, medium power
Numerous cells of high grade urothelial carcinoma.
In this example, the cells are small and appear histiocytoid. However, the N:C ratios are high, nuclear membranes are thickened, nuclear outlines are irregular and the nuclear sizes are variable
Pap stain, high power
Large cell of high grade urothelial carcinoma with high N:C ratio, irregular nucleus and thickened nuclear membrane.
Note two smaller cells which appear histiocytoid and may be misinterpreted as degenerated cells
Pap stain, high power
High grade carcinoma cell with irregular nuclear outline and irregular distribution of chromatin
Pap stain, high power
Another example of a cluster of high grade urothelial carcinoma
Pap stain, high power
Another example of single cell pattern of high grade carcinoma. Note the cells in middle may be difficult to distinguish from polyoma virus infection; however, nuclear membrane irregularity and coarse chromatin are features of carcinoma rather than of viral inclusions
Features
• Variable cellularity
• Predominantly single cell pattern (coy cells)
• Occasional small groups with dissociation of cells on periphery
• Plasmacytoid morphology
• Cytoplasm may contain Melamed bodies
• High nucleus to cytoplasmic ratio
• Nuclear pleomorphism
• Irregular nuclear contours
• Coarse chromatin
• Hyperchromasia
• Indistinct to variably prominent nucleoli
• May have necrosis and inflammation
• Express cytokeratin, Cam5.2, CK7, CK20, GATA3, uroplakin +/- , AMACR +/- , usually negative for RCC, TTF-1, Pax-8, PSA, PAP