Metastasis of colorectal carcinoma to the testes: clinical presentation and possible pathways.

Distant metastasis from colorectal carcinoma most often occurs in the liver and lungs. Metastasis to bones, adrenals, lymph nodes, brain, and skin has also been reported. Metastatic colorectal carcinoma to the testes is very uncommon. Even more uncommon is testicular metastasis from rectal carcinoma. Researchers throughout the last few decades have not acquired a clear understanding of the lymphatic pathways involved in reported cases of testicular metastasis from primary colorectal carcinoma. These cases may present with testicular complaints after or even before the diagnosis of colorectal cancer; this is why it is crucial to differentiate between primary testicular tumor and a secondary one from a colorectal primary. We searched the English medical literature using the MEDLINE/PUBMED database from 1950 through January 2010. Our search yielded 33 cases of testicular metastasis from rectal or colonic carcinoma. These cases are reviewed and summarized. This paper reviews the literature for all cases of testicular metastasis from colonic and rectal adenocarcinomas shedding light on the possible pathways of metastasis. We recommend that physicians be aware of the risk of metastasis from the colorectal region to the testis in their evaluation of patients with testicular symptoms in the setting of colorectal carcinoma.