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flat urothelial dysplasia

Wednesday 23 May 2018


- Webpathology


- low grade

  • simple flat urothelial dysplasia / / low-grade flat urothelial dysplasia
  • The urothelial lining is somewhat thickened consisting of 8 to 10 layers of cells.
  • There is loss of polarity with minimal nuclear pleomorphism, nuclear enlargement and hyperchromasia.
  • Mitotic activity is not increased.
  • There is no inflammation to account for these cytologic changes.
  • The degree of atypia is not severe enough to justify the diagnosis of CIS and such lesions are best classified as dysplastic / low-grade urothelial dysplasia.

- high grade / high-grade flat urothelial dysplasia

  • = urothelial carcinoma / in situ UCIS / urothelial CIS
  • Urothelial CIS shows cytologic atypia consisting of nuclear enlargement and hyperchromasia, pleomorphism, apoptotic cells, prominent nucleoli, and hypervascularity of lamina propria.
  • There is severe cytologic atypia consisting of loss of polarity, nuclear enlargement and hyperchromasia, and nuclear pleomorphism.
  • Apoptotic cells and mitotic figures are readily seen.
  • The urothelial thickness is decreased and the cytologic atypia involves all layers.
  • The lamina propria shows numerous capillary-caliber vessels and this feature is responsible for the erythematous appearance of CIS on cystoscopy.
  • The urothelial lining consists of large atypical hyperchromatic cells with considerable variation in nuclear size and shape.
  • The complete loss of polarity is obvious here. There is overcrowding and the cells appear piled up on top of one another.
  • The lamina propria is hypervascular and contain scattered chronic inflammatory cells.
  • Urothelial CIS is a discohesive lesion frequently shedding neoplastic cells in the urine with thinning of the urothelial lining.
  • The neoplastic cells show pleomorphic hyperchromatic nuclei and abundant eosinophilic cytoplasm.
  • Notwithstanding the acute inflammation in the underlying lamina propria, the degree of cytologic and architectural atypia seen here is diagnostic of CIS.
  • Immunostaining with CK20 shows full thickness staining of CIS. The underlying Brunn nests are negative. In reactive lesions, CK20 expression is usually limited to the surface umbrella cells.

- Some cases of urothelial carcinoma-in-situ show neoplastic cells that are somewhat monomorphic as seen here. The cells have abundant eosinophilic cytoplasm and conspicuously lack significant pleomorphism; however, the nuclei are enlarged and show one or more prominent nucleoli. Mitotic features are readily seen. The normal orientation of cells on the basement membrane (polarity) also appears to be altered.

- Urothelial carcinoma-in-situ (CIS) can involve Brunn nests (bottom).

  • The neoplastic cells show nuclear enlargement and hyperchromasia, pleomorphism, apoptosis, and increased mitotic activity.
  • The presence of neoplastic cell clusters within lamina propria may be overdiagnosed as invasion.
  • Brunn nests with urothelial CIS can be recognized by their round contours and the lack of stromal changes around them.

- pagetoid spread of urothelial CIS along the surface urothelium.

  • Urothelial CIS may spread into the adjacent normal urothelium in a pagetoid fashion.
  • Several individual tumor cells with features of CIS are present within the normal urothelium.
  • The tumor cells have voluminous eosinophilic cytoplasm and enlarged hyperchromatic nuclei.
  • The tumor cells have abundant eosinophilic cytoplasm and atypical nuclei.
  • The benign urothelial cells are present along the basal region.
  • Immunostainin with CK20 highlights the tumor cells in the next image.
  • Diffuse p53 immunoreactivity can help distinguish urothelial CIS from reactive atypia. Same case as the previous image.

See also

- flat urothelial anomalies