Human chorionic gonadotropin-induced hyperthyroidism in germ cell cancer--a case presentation and review of the literature.
BACKGROUND
Human chorionic gonadotropin (hCG)-induced hyperthyroidism represents a rare paraneoplastic syndrome in hCG-secreting testicular cancer. In most cases, this hyperthyroidism remains subclinical. hCG belongs to the family of glycoprotein hormones with structural homology to thyroid- stimulating hormone (TSH). The thyrotropic potency and thereby the degree of cross reactivity of hCG is determined by several factors, such as content of sialic acid or lack of the C-terminal tail. In the absence of clinical signs of hyperthyroidism, treatment usually consists of specific antitumor therapy which will result in normalization of thyroid function if hCG declines. Where there are clinical signs of hyperthyroidism, overlapping thyreostatic treatment is recommended.


METHODS
Here, we report of a young man presenting biochemical signs of hyperthyroidism without clinical signs at the time of diagnosis of non-seminomatous germ cell cancer. Beta-hCG initially exceeded 1,000,000 IU/ml and declined close to normal at the end of cancer treatment. Concomitantly, thyroid hormones returned to the normal range without any thyreostatic therapy. We observed a significant correlation of neta-hCG and thyroid hormones in linear regression analysis (r2 = 0.98, p< 0.05). A concise overview of potential mechanisms of hCG-induced hyperthyroidism in germ cell cancer but also in pregnancy is given and the case discussed according to the cited literature.
Voigt
Wieland
W
Department of Hematology/Oncology, Martin Luther University, Halle-Wittenberg, Germany.
Maher
Gita
G
Wolf
Hans-Heinrich
HH
Schmoll
Hans-Joachim
HJ
D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology / Q000556:secondary / Q000628:therapy; D000328:Adult; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D003131:Combined Modality Therapy; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D006980:Hyperthyroidism / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D008297:Male; D009367:Neoplasm Staging; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology / Q000556:secondary / Q000628:therapy; D010257:Paraneoplastic Syndromes / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000556:secondary / Q000628:therapy; D013736:Testicular Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D013963:Thyroid Hormones / Q000097:blood
D006063:Chorionic Gonadotropin; D013963:Thyroid Hormones