Gestational choriocarcinoma and thyrotoxicosis.

A case of a 26-year-old woman with metastatic choriocarcinoma and clinical and biochemical thyrotoxicosis is described. This represents the eighth reported case of the association of choriocarcinoma and thyrotoxicosis. Serial monitoring of serum thyroxine (T4) and thyroid stimulating hormone (TSH) levels correlated precisely with the beta sub-unit human chorionic gonadotropin (hCG) level and the quantitation of host tumor burden. The development of a hypermetabolic syndrome in patients with choriocarcinoma may be due to secondary thyrotoxicosis from either the TSH-like activity of hCG or from the concomitant production of molar thyrotropin by the tumor.