Ectopic production of human chorionic gonadotropin by synovial sarcoma of the hip

Human chorionic gonadotropin (hCG) is a marker of pregnancy and a tumor marker for some gynecologic malignancies, including germ cell tumors and gestational trophoblastic neoplasia. Rarely, hCG is secreted by nongynecologic tumors, confounding the diagnosis.

A 45-year-old woman was evaluated for a persistently elevated β-hCG. Diagnosis of her primary malignancy, synovial sarcoma of the hip, was delayed as more common etiologies were considered, including ectopic pregnancy and gestational trophoblastic neoplasm. The workup eventually led to the diagnosis using imaging studies but ultimately resulted in a 3-month delay and unnecessary medical and surgical treatments.

This case highlights the importance of nongynecologic malignancies when evaluating patients with a persistent β-hCG.