Testicular Germ Cell Tumors: Paraneoplastic Syndromes and the Role of Beta-Human Chorionic Gonadotropin

Choriocarcinoma syndrome is a rare phenomenon that occurs in male patients with testicular choriocarcinoma. Male patients who have a testicular non-seminomatous germ cell tumor (TNSGCT) with at least partial choriocarcinoma histology, and metastases to the lungs and/or other extragonadal sites, as well as a markedly elevated beta-human chorionic gonadotropin (HCG), have been prone to pulmonary bleeding, hypoxia, and acute respiratory distress syndrome (ARDS). The respiratory complications occur immediately after chemotherapy is administered or, in some cases, spontaneously. Paraneoplastic hyperthyroidism is another entity described in patients with testicular choriocarcinoma, whereby high levels of HCG (typically >50,000 mIU/ml) induce clinical and laboratory characteristics of hyperthyroidism. We present the case of a male patient diagnosed with TNSGCT and found to have both choriocarcinoma syndrome and paraneoplastic hyperthyroidism in the setting of only mildly elevated HCG levels. We compare our case with similar cases published previously while questioning the quantitative role of HCG.