American Urological Association - Papillary Urothelial Carcinoma, Low Grade


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Papillary Urothelial Carcinoma, Low Grade

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  • 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.
  • Histology:
    • 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%.