Mucinous adenocarcinoma probably arising in the renal pelvis and ureter: a case report.

A patient with widely disseminated mucinous adenocarcinoma had polypoid tumors in the left renal pelvis and ureter. While no certain primary site was determined, either clinically or at postmortem examination, microscopic examination of the left renal pelvis and ureter revealed atypical glandular metaplasia adjacent to the tumors and made the upper urinary tract a likely site of origin for the adenocarcinoma.