American Urological Association - Urothelial Hyperplasia


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Urothelial Hyperplasia

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  • Markedly thickened urothelium lacking cytologic atypia.
    • No absolute numerical cut-off for hyperplasia, which is usually marked and easily distinguishable (image A) & (image B).
  • Can be flat or papillary.
  • Flat hyperplasia may be seen adjacent to low grade papillary tumors.
  • Papillary urothelial hyperplasia is characterized by hyperplastic urothelium arranged in undulating mucosal folds.
    • Lack of cytologic atypia and fibrovascular core (not true papillae) distinguish from papillary urothelial neoplasms, which is the main differential diagnosis.
    • Suggested to be precursor lesion for low-grade papillary urothelial tumors (not the usual flat hyperplasia).