Differentiation primary adenocarcinoma of the bladder, urothelial carcinoma and secondary colorectal carcinoma

Epidemiology

Primary adenocarcinoma of the bladder constitutes only 0.5-2% of all primary bladder malignancies, while spread from a colorectal primary is the most common (20%-33%) of all secondary tumours involving the bladder.

Histopathology

Primary adenocarcinoma of bladder is often of enteric type, morphologically indistinguishable from a colorectal primary.

Immunohistochemistry

The combination of CK7, CK20, thrombomodulin and b-catenin will discriminate between adenocarcinomas of bladder and colorectum.

		adenocarcinoma		urothelial carcinoma
		primary of bladder	secondary from colorectum	urothelial carcinoma
CK7		11/17	0/16	10/10
CK20		9/17	15/16	4/10
thrombomodulin		10/17	0/16	10/10
b-catenin	nuclear	0/17	13/16	0/10
	membranous	15/17	16/16	10/10
	negative	2/17	0/16	0/10

the only ambiguous combination in this study was CK7-/CK20+/T-/C(N)-

References

Wang, H. L., Lu, D. W., Yerian, L. M., Alsikafi, N., Steinberg, G., Hart, J., Yang, X. J. Immunohistochemical distinction between primary adenocarcinoma of the bladder and secondary colorectal adenocarcinoma. Am J Surg Pathol 2001;25:1380-1387.

This page last revised 9.5.2002.