Erythropoietin-induced secondary polycythemia in a patient with a renal cell carcinoma. A case report

This study provides clear documentation of in vivo biogenesis of erythropoietin (Epo) by a human renal carcinoma. A middle-aged woman with a clear cell renal carcinoma of the left kidney developed severe polycythemia. This polycythemia was accompanied by markedly elevated levels of immunoreactive erythropoietin both in the peripheral venous blood, and in blood derived from the left renal vein during nephrectomy. Exstirpation of the non-invasive renal carcinoma was followed by complete restoration of both hematocrit and erythropoietin plasma concentration to normal levels. The fall in plasma erythropietin concentration immediately after nephrectomy (T/2 less than or equal to 3 hours) was probably a valid representation of plasma erythropoietin metabolism in this patient. Direct evidence of erythropoietin production in individual renal carcinoma cells was provided by immunoperoxidase studies demonstrating focal cytoplasmatic accumulation of immunoreactive erythropoietin in the tumor cells.