Modification in lymphatic drainage following retroperitoneal lymph node dissection, such as a collateral circulation or lymph node and lymphatic vessel regeneration, was observed in 2 patients in whom a second tumor developed in the remaining testicle. Such alterations of the lymphatic system are difficult to evaluate for the possible presence of metastatic disease. The presence of extensive collateral circulation rules out lymph node dissection or radiation therapy as an appropriate treatment in these patients. A short course of systemic chemotherapy, regardless of the histological type of the second malignancy, seems to be the safest adjunctive treatment in such cases.