Urothelial non-neoplastic lesions

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 5 August 2016, last major update June 2016

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Bladder [title] dysplasia
Cite this page: Dysplasia. website. Accessed October 24th, 2016.
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
Micro 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
Negative Stains
Differential Diagnosis
Additional References