Bladder, ureter & renal pelvis
Urothelial neoplasms - noninvasive

Topic Completed: 1 June 2016

Minor changes: 7 February 2020

Revised: 20 December 2018

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Bladder [title] dysplasia

Monika Roychowdhury, M.D.
Page views in 2020: 5,226
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Cite this page: Roychowdhury M Dysplasia. website. Accessed May 16th, 2021.
Definition / general
  • Lesions of flat, noninvasive urothelium with appreciable cytologic and architectural changes indicative of neoplasia, but less than carcinoma in situ
  • Represents an early morphologic manifestation of progressive alterations between normal urothelium and carcinoma in situ
  • Also known as low grade intraurothelial neoplasia (LG IUN)
  • Mean age 60 years, 75% male
  • More common on posterior wall
Clinical features
  • Occurs de novo (primary) or in patients with concurrent or previous urothelial neoplasms (secondary)
  • 2/3 have irritative symptoms or hematuria; 1/3 have no symptoms
  • 14-19% develop biopsy-proven progression (Cancer 2000;88:625, Am J Surg Pathol 1999;23: 443)
Prognostic factors
  • Secondary dysplasia is more common than primary and has a higher rate of progression to carcinoma than de novo dysplasia (30-36% versus 14-19%)
  • Only 3-10% die of bladder cancer over a 10-25 year period
Microscopic (histologic) description
  • Characterized by lack of maturation in basal and intermediate cell layers (not full thickness)
  • Normal urothelial thickness (may be increased or decreased) and superficial umbrella cells are present
  • Atypical cytological changes restricted to intermediate and basal cells
  • Variable mitotic activity
  • Normal lamina propria
  • Low interobserver agreement on diagnosis, even among experts
Cytology description
  • Usually normal
  • Loss of cytoplasmic clearing and nuclear polarity
  • Nuclear enlargement, nuclear membrane irregularities and nuclear hyperchromasia
Positive stains
  • CK20 (aberrant expression in deeper layers), p53 (wild-type expression pattern)
Negative stains
Differential diagnosis
Additional references
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