Testicular tumors in 2 families.

Testicular cancers in closely related family members are rare. We herein report the second incidence of pure seminoma occurring in a father and son. The increased risk of malignant tumors developing in the undescended testis is well established. We also describe the second reported incidence of testicular cancers occurring in 2 non-twin brothers, in which 1 of the cancers developed in an undescended testis.