Urothelium: normal v reactive v carcinoma in situ (CIS)

Urothelium shows a complex pattern of cytokeratin expression.

	cytokeratin 20	CD44s	p53
normal urothelium (10 cases)	umbrella cells only	membranous staining of the basal layer only	none to focal and very weak
reactive urothelium (15 cases)	umbrella cells only	membranous overstaining of the full thickness of the urothelium (9 cases) patchy positivity of basal and intermediate cells (6 cases).	none to patchy and weak, predominantly in the basal layer.
carcinoma in situ (21 cases)	cytoplasmic overexpression by more than 50% of cells in 17 cases	no staining except in basal layer	overexpression in 12 cases

The combination of positivity for CK20 and p53 with negativity for CD44s in atypical cells favours CIS, whereas the reverse favours reactive atypia. In Pagetoid spread of CIS, the neoplastic cells are highlighted by CK20 and p53.

References

McKenney, J. K., Desai, S., Cohen, C., Amin, M. B. Discriminatory immunohistochemical staining of urothelial carcinoma in situ and non-neoplastic urothelium: an analysis of cytokeratin 20, p53, and CD44 antigens. Am J Surg Pathol 2001;25:1074-1078.

This page last revised 27.12.2001.