Human Chorionic Gonadotropin-Induced Hyperthyroidism in Germ Cell Cancer – a Case Presentation and Review of the Literature

Abstract

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 familiy 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. Case Report: 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. β-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 β-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.

Cisplatin-Based Chemotherapy for Pulmonary Metastasized Germ Cell Tumors of the Testis – Be Aware of Acute Respiratory Distress Syndrome

“…α-Fetoprotein (AFP) levels were found to be within the reference range (2.4 ng/ml). An observed latent hyperthyroidism was possibly associated with the significant elevation of β-HCG levels [6]. The first staging computed tomography (CT) scan showed a diffuse nodular infiltration in the lungs ( fig.…”

Receptorial and Functional Overlapping between Thyrotropin (TSH) and Gonadotropins (FSH, LH): Phylogenetic, Ontogenetic and Clinical Application Aspects

“…Both hyper and hypothyroidism can cause infertility and spontaneous abortions [44]. HCG induced hyperthyroidism represents a rare paraneoplastic syndrome of hCG secreting testicular cancer [45]. TSH has a modulatory influence on the sexual and spermatogenic function of males [46].…”

Testicular Germ Cell Tumors

“…Serum β-hCG levels are typically high (usually >100,000 mIU/mL). Gynecomastia and hyperthyroidism have been described, and this is secondary to structural and functional similarities between the alpha chain of hCG and TSH and FSH [153][154][155][156][157].…”

“…This symptom is usually associated with high serum hCG levels, and thus it is more common in tumors containing trophoblastic components, particularly CC, but also other forms containing syncytiotrophoblastic giant cells. Rarely, high β-hCG levels may produce thyrotoxicosis due to TSH-like activity of the hCG [153,154,260,261]. Carcinoid syndrome is unusual in cases of testicular carcinoid [205,212].…”