How often do extratesticular malignancies metastasize to the testicle

How often do extratesticular malignancies metastasize to the testicle?

Metastatic disease to the testicle is uncommon, occurring in <1% of patients with extratesticular malignancy, and is generally associated with a poor clinical outcome. The most common primary tumors that spread to the testicle are prostate cancer, lung cancer, melanoma, colorectal cancer, and renal cell carcinoma.