Introduction: Colorectal cancer is one of the most common cancers worldwide. Metastasis of colorectal cancer to the testis is very rare and only few cases were reported in literature in which a primary colorectal cancer metastasized to the testes. To date, only 42 cases of primary colon cancers metastasizing to testes were reported in literature.
Case Report: A 47-year-old male who underwent palliative left hemi-colectomy for metastatic colon adenocarcinoma in March, 2008 presented with painful right testicular swelling in April, 2009. He denied any lower urinary tract symptoms. Abdominal examination showed ascites with no evidence of tenderness. Genital examination revealed right testicular mass, around 3x2 cm in size, which was slightly tender with positive transillumination test. The left testis was normal. There was no evidence of scrotal skin changes and phallus was unremarkable. Tumor markers showed elevated carcinoembryonic antigen, but normal alpha fetoprotein, lactate dehydrogenase and beta human chorionic gonadotrophin. Scrotal ultrasound showed right testicular hypoechoic mass (2.1x1.7 cm) with irregular outlines. No fine needle aspiration cytology was done. Palliative right radical orchidectomy was done through an inguinal approach. The histopathology showed metastatic moderately differentiated adenocarcinoma with mucinous differentiation. One week postoperatively he was transferred to the palliative care.
Conclusion: Metastatic gastrointestinal adenocarcinoma to the urogenital tract especially the testis is extremely rare. However, it should be considered in any patient with similar presentation.

Keywords: Colorectal carcinoma, Testicular metástasis