A rare case of metastatic sigmoid adenocarcinoma to the ureter.

Colorectal cancer is a very common disease process, as is ureteral obstruction, but the two are typically mutually exclusive. The case report presented details a 35-year-old male with left sided flank pain and hydroureteronephrosis caused by metastatic spread of previously diagnosed and treated sigmoid adenocarcinoma. About two years previously, he had been diagnosed with Stage IV, T4a sigmoid colon cancer with liver metastasis and had resection of his primary tumor as well as metastatic sites and several rounds of chemotherapy. This case is an example of the different ways that cancer can grow, evading detection by spreading in atypical patterns.