Nested Variant Urothelial (Transitional Cell) Carcinoma
Differential Diagnosis
- Inverted pattern urothelial carcinoma
- Inverted papilloma
- Florid von Brunn nests
- Florid cystitis cystica/glandularis
| Nested Variant Urothelial Carcinoma | Transitional/Urothelial Carcinoma with Inverted Pattern |
|---|---|
| Invasive carcinoma that looks deceptively non-invasive due to predominantly nested pattern | Non-invasive inverted pattern of carcinoma that looks deceptively invasive |
| Overall invasive pattern, not circumscribed | Lacks clearly invasive pattern |
| May involve muscularis propria | Does not involve muscularis propria |
| Varying sizes and shapes of nests | Frequently formed by fusion of trabeculae and cords (inverted papilloma like pattern) |
| Desmoplastic stroma may be present | No desmoplasia |
| Nested Variant Urothelial Carcinoma | Inverted Papilloma |
|---|---|
| Overall invasive pattern, not circumscribed | Circumscribed (if sample permits assessment) |
| May involve muscularis propria | Does not involve muscularis propria |
| Varying sizes and shapes of nests | Uniform trabeculae and cords |
| Disorder of cells in nests | Orderly peripheral palisading and central streaming |
| Nested Variant Urothelial Carcinoma | Florid von Brunn Nests, Cystitis Cystica/Glandularis |
|---|---|
| Infiltrative pattern | Tend to have uniform depth and/or lobular architecture |
| Frequently invades muscularis propria | Usually confined to superficial submucosa, does not involve muscularis propria |
| Overall cytologically bland but usually at least focally atypical | Cytologically bland |
The distinction may be very difficult on superficial biopsies
IPOX for Ki67, p53, p27 and CK20 is not helpful (Volmar)
