Isolated Renal and Ureter Metastasis as the First Manifestation of Rectal Adenocarcinoma.

Colorectal carcinoma (CRC) rarely metastasizes to the urinary system in isolated form. It usually spreads through direct invasion with intra-ureteric growth or local ureter mucosal metastasis without involving the muscular layer. We present a case of a 63-year-old man who came with uraemic symptoms and a ballotable right kidney. Laboratory and imaging showed acute renal failure with right renal mass suspicious of malignancy and left ureteric stricture causing hydronephrosis. He underwent right radical nephrectomy and left open ureteric stenting plus biopsy sampling. Adenocarcinoma was detected through the evaluation of the specimen. In view that adenocarcinoma rarely occurs in the urinary system, an investigation was carried out to search for the primary source. Colonoscopy was performed, which later showed adenocarcinoma of the rectum. Adenocarcinoma in the renal system should always raise the suspicion of another primary source of malignancy, especially colorectal origin. The advanced stage of this cancer should be managed with the best palliative treatment rather than aggressive surgical intervention.