False positive beta-human chorionic gonadotropin in testicular cancer

Persistent elevations in serum markers after chemotherapy for germ cell testicular carcinoma indicate residual disease. We report on a patient with advanced seminoma with choriocarcinoma who had elevated serum beta-human chorionic gonadotropin (β-HCG) and residual masses on computerized tomography scan after chemotherapy. Wedge liver resection and retroperitoneal node dissection yielded only necrotic tissue which assayed and immunoperoxidase stained positively for β-HCG. Serum β-HCG fell to undetectable levels postoperatively, and the patient remains disease free after three years. Phagocytosis of necrotic tumor apparently released entrapped β-HCG resulting in a false positive tumor marker.