Urothelial dysplasia

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Urothelial dysplasia, also low-grade (urothelial) dysplasia, is a lesion of the urothelium in the ISUP/WHO 2004 classification.[1] It is precursor lesion to urothelial carcinoma that is less worrisome than urothelial carcinoma in situ (also known as high-grade (urothelial) dysplasia).

General

The ISUP/WHO classification of flat urothelial lesions is:[1]

  • Reactive urothelial atypia.
  • Flat urothelial hyperplasia.
  • Urothelial atypia of unknown significance.
  • Urothelial dysplasia (low-grade dysplasia).
  • Urothelial carcinoma in situ (high-grade dysplasia).
  • Invasive urothelial carcinoma.

Microscopic

Features:[2]

  • Mild nuclear enlargement (~3x a resting lymphocyte) and hyperchromasia.
  • Slight disorganization of the architecture.
    • Some maturation to the surface.
  • Mitotic figures - occasional, none atypical.

Notes:

  • It is probably not a good idea to make this diagnosis without immunohistochemistry.
  • This diagnosis not made on frozen section.

DDx:

Images

IHC

A comparison between benign, dysplasia and UCIS:[3]

Diagnosis CK20 Ki-67 p53
Benign (reactive) umbrella cells +ve only -ve <=10% of cells (+/-rare basal cells) -ve <20% of cells (+/-weak staining)
Urothelial dysplasia +ve non-umbrella cells +ve (~30% of cases) +ve >10% of cells (~40% of cases) +ve >=20% of cells (~70% of cases)
Urothelial carcinoma in situ (UCIS) +ve non-umbrella cells (~70% of cases) +ve >10% of cells (~95% of cases) +ve >=20% of cells (~80% of cases)

See also

References

  1. 1.0 1.1 Hodges, KB.; Lopez-Beltran, A.; Davidson, DD.; Montironi, R.; Cheng, L. (Feb 2010). "Urothelial dysplasia and other flat lesions of the urinary bladder: clinicopathologic and molecular features.". Hum Pathol 41 (2): 155-62. doi:10.1016/j.humpath.2009.07.002. PMID 19762067.
  2. URL: http://pathology.jhu.edu/bladder/image1.cfm?case_number=10&image_number=1. Accessed on: 31 December 2013.
  3. Mallofré, C.; Castillo, M.; Morente, V.; Solé, M. (Mar 2003). "Immunohistochemical expression of CK20, p53, and Ki-67 as objective markers of urothelial dysplasia.". Mod Pathol 16 (3): 187-91. doi:10.1097/01.MP.0000056628.38714.5D. PMID 12640096.