American Urological Association - Papillary Urothelial Carcinoma, Low Grade
Papillary Urothelial Carcinoma, Low Grade
- Papillary urothelial neoplasm with distinct low-grade dysplastic features.
- More common in men, at trigone or bladder neck region and presents with hematuria (so as all other papillary neoplasms).
- Not synonymous with older 1973 WHO grade 1 transitional cell carcinoma (TCC) category.
- LGPUC includes mostly former TCC grade 1 and some grade 2.
- Some former TCC grade 1 also became PUNLMP.
- Associated with mutations in EGFR and HRAS.
- Size varies, but generally is visualized as smaller lesions.
- Papillae (with fibrovascular core) may variably exhibit branching and fusion.
- Mild loss of cellular polarity.
- Nuclear rounding, slight size variation and mildly abnormal chromatin (image A) & (image B).
- Mitosis is occasional and when present is usually closer to base.
- Recurrence rate of 48-71% and progression rate to invasive cancer and death is <5%.