Metastatic Colorectal AdenoCA in Bladder

Metastases from colorectal cancers usually express beta-catenin, CDX2, CK20 and are negative for CK7. Primary bladder adenocarcinomas would be beta-catenin negative and express both CK7 and CK20. However, immunostains do not offer unequivocal answers and one has to consider clinical and radiologic findings before making the final diagnosis. When adenocarcinoma with enteric features is encountered in the urinary bladder and there is no prior history of colorectal adenocarcinoma, it is advisable to convey to the clinician that secondary involvement of bladder from a primary GI tract malignancy should be looked into.