Microcystic Urothelial (Transitional Cell) Carcinoma
Definition
- Invasive urothelial carcinoma with numerous lumens of variable size without glandular differentiation
Note
- Usual papillary urothelial carcinoma is covered separately
Diagnostic Criteria
- Infiltrative pattern
- Numerous, prominent spaces ranging from intracytoplasmic to macroscopic (2 cm)
- May appear as irregular anastomosing cords and nests of cells forming cysts
- May appear as large irregular cribriform areas
- 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
- Cytologically bland
- Probably forms a spectrum with nested variant urothelial carcinoma (fewer cysts and spaces) and with lesions described as urothelial carcinoma with acinar/tubular differentiation (extensive formation of small tubules)
- All three are aggresive, invasive carcinomas in spite of their bland cytology
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates:
