FALSE-POSITIVE SERUM PROSTATE-SPECIFIC ANTIGEN VALUES IN A PATIENT WITH NON-HODGKIN-LYMPHOMA OF THE KIDNEY

Prostate-specific antigen (PSA) is the clinically most useful tumor ma rker for prostate cancer. Although false-positive elevations have been reported due to disease processes outside the prostate gland with the use of the polyclonal assay, such false-positive test results have be en exceedingly rare with the use of the monoclonal assay. We report th e case of a patient diagnosed with a B-cell lymphoma of the kidney and a significant elevation of serum PSA levels by monoclonal assay in th e absence of either inflammatory or malignant prostate disease. PSA re turned to normal during lymphoma-specific chemotherapy with a cyclopho sphamide, mechlorethamine, vincristine, procarbazine, prednisone regim en. Possible explanations and clinical implications are discussed.