Nested Variant Urothelial (Transitional Cell) Carcinoma
Definition
- Urothelial carcinoma with deceptively bland appearing invasion by nests of cells
Note
- Usual papillary urothelial carcinoma is covered separately
Diagnostic Criteria
- Infiltrative pattern
- May be difficult to assess on biopsies
- Frequently has deep foci of classical jagged invasion
- Muscularis propria involvement is definitional if present
- Stroma may be normal or desmoplastic
- May be difficult to assess on biopsies
- Predominant pattern is variably sized nests, frequently small and fused
- Frequently forms spaces or lumens
- Carcinoma cells forming and lining spaces lack glandular/secretory cytoplasmic differentiation
- Lumens frequently empty, but may contain necrotic debris or PASd stainable material
- Lining cells are transitional or squamous, PASd negative
- No goblet cells
- If extensive, can be termed microcystic urothelial carcinoma
- Cytologically predominantly bland
- Focal cytologic atypia nearly always present
- Sometimes only in deeper tissues
- Focal cytologic atypia nearly always present
- Overlying mucosa is normal or may have papillary component
- Frequently involves ureteral orifices
- Aggresive, invasive carcinomas in spite of bland cytology
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates: 10/20/12