Metastatic Sigmoid Adenocarcinoma at the Right Ureter

Colorectal cancer and ureteral obstruction are both relatively common clinical entities. Although advancing carcinomas from neighboring organs can infiltrate and eventually block the ureter, distant ureteral metastasis from colon adenocarcinoma is a very rare condition. We present a case of a 68-year-old Caucasian female, with a right ureteral metastasis and a history of sigmoid cancer. The patient was referred to our department with asymptomatic moderate right hydronephrosis and hydroureter. She underwent right ureteroscopy, which revealed the abnormal tissue, and right nephroureterectomy. Histology showed infiltration of all layers of the ureteral wall, including the mucosa, by neoplastic cells with morphological and immunohistochemical features of colon adenocarcinoma. The patient was referred to the oncological department for oncological reevaluation.