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Genitourinary Cancer

False-Positive Serum Human Chorionic Gonadotropin (hCG) in a Male Patient with a Malignant Germ Cell Tumor of the Testis: A Case Report and Review of the Literature

Departments of ^aClinical Chemistry and ^bClinical Oncology, Leiden University Medical Center, Leiden, The Netherlands

Key Words. Human chorionic gonadotropin • Germ cell neoplasms • Testicular neoplasms • Heterophilic antibodies • IgA deficiency • Tumor markers

Correspondence: S. Osanto, M.D., Ph.D., Department of Clinical Oncology, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333 ZA Leiden, The Netherlands. Telephone: 31-71-526-3464; Fax: 31-71-526-6760; e-mail: s.osanto{at}lumc.nl

Received July 24, 2008; accepted for publication September 30, 2008; first published online in THE ONCOLOGIST Express on November 4, 2008.

Disclosure: The content of this article has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from commercial bias. No financial relationships relevant to the content of this article have been disclosed by the authors, planners, independent peer reviewers, or staff managers.

A 39-year-old male patient with a favorable prognosis stage IIB metastatic malignant germ cell tumor (GCT) and elevated pre- and postorchiectomy serum human chorionic gonadotropin (hCG) was treated with three courses of combination chemotherapy resulting in a rapid normalization of his serum hCG.

Within 2 months after the cessation of chemotherapy, his serum hCG increased again, suggesting tumor recurrence. Pathological examination of the resected residual retroperitoneal lymph nodes revealed no vital tumor cells. Based on the further rise in his serum hCG and enlargement of mediastinal lymph nodes on computed tomography scan, the patient underwent second- and third-line chemotherapy, which did not result in normalization of his serum hCG. Reanalysis of stored serum samples with other immunoassays revealed that the elevated serum hCG levels collected before first-line chemotherapy were indeed elevated, but those collected after first-line chemotherapy were all falsely positive. Currently, the patient is still alive and disease free.

This is the first report of a male cancer patient who received unneeded second- and third-line chemotherapy for relapse based on false-positive hCG results. We discuss the pitfalls of false-positive serum hCG measurements, including heterophilic antibodies, as in our IgA-deficient patient, and review the literature.