Abstract
Mediastinal and hilar renal cell carcinoma metastases are reported in 9 patients, representing an incidence rate of 8% in the series. This observation indicated an ominous prognosis since the mean survival of these patients was only 1.4 mo. after the discovery of the neoplasm. This poor prognosis is attributable to the size of the primary lesion, with direct extension into retroperitoneal structures and perhaps to an associated exhaustion of immunologic defense mechanisms of the patients. Dissemination from the involved retroperitoneal lymphatics to the thoracic duct and then in retrograde fashion via the bronchomediastinal and paratracheal trunks is advocated as the pathway for this tumor dissemination.