Clinically unrecognised renal carcinoma: aspects of tumor morphology, lymphatic and haematogenous metastatic spread.

In a series comprising 235 clinically unrecognised renal carcinoma, metastatic spread was found in 56 cases (24%). In 82% of cases with metastases the spread involved more than one site. Lymphatic spread was diagnosed in 37 patients. Lymph node metastases were usually multiple and multifocal and were almost as common in the mediastinum as in the retroperitoneal space. In cases with involvement of these sites and/or supraclavicular nodes, concomitant metastases in the lungs were observed in 86% and in other organs in 11%. Since lymph node invasion is a strong indicator of systemic spread, the therapeutic benefit of radical lymphadenectomy seems very low, whereas a limited unilateral dissection is justified mainly for its value as a staging procedure.