Erythropoietin-producing renal cell carcinoma in chronic hemodialysis patients: a report of two cases.

Erythropoietin (EPO)-producing renal cell carcinomas in two hemodialysis patients are reported. Despite deteriorated kidney function, these patients did not manifest anemia at diagnosis and their elevated serum EPO levels rapidly returned to within the normal range after nephrectomy. Immunohistochemical staining of the resected specimens showed production of erythropoietin in the tumor cells in one case and in the lining cells of the cyst wall in the other case.